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You are here: Home | Environment | Agenda | Coastal communities | Ocean pollution

Ocean pollution

Nearly 250 million people live within 50 km of India’s 8,000 km coastline. Eighty-seven cities and towns located in these coastal areas together dump 5.5 billion litres of wastewater into the sea every day. Less than a tenth of this water is treated, making the scale of pollution of our coastal ecosystems daunting, writes Rahul Goswami

Just as it is with worldwide species diversity, so it is with India’s coastal ecosystems and habitats -- the growth in knowledge and understanding of both runs simultaneous with their destruction. Only from the early-1990s, when the oceanographic sciences became stronger in the country’s scientific matrix, and when multi-sectored studies and research began to be attempted as a means -- perhaps the only way -- of figuring out complex problems, has there been a general understanding of the large-scale dynamics of coastal circulation in the Arabian Sea and the Bay of Bengal.

To understand our coasts, the physical sciences combine with social sciences. Both work together: the anthropocentric social science view of global change complements the geocentric natural sciences view. Coastal zones are important for both, and it is in the last decade that such a convergence of understanding has begun to be explained. The trouble is, this understanding has come at a time of widespread economic growth and industrial expansion, so that as knowledge of India’s coasts (and our human impact on them) increases so too does the intensity and scale of the impact. 

The scale is daunting. Most of India’s 8,000-km-long coastal regions are low-lying and densely populated, with nearly 250 million people living within 50 km of the coast, many of them in the 130 cities and towns that together form the engine of India’s economy, including Mumbai, Kolkata, Chennai, Goa, Surat, and Thiruvananthapuram (see map). Between 20-60% of the population in these individual settlement zones live in slums where they pursue their livelihood, and this section is automatically located in areas most vulnerable to natural disasters; areas that are already subject to periodic flooding.  

At the same time, they are surrounded by a web of infrastructure that is becoming denser and more valuable every year: transport and freight networks, road and rail corridors, industrial zones and parks, maritime and port facilities, petroleum industries and refineries, import-based industrial and commercial domains -- all located in coastal areas and competing for land and water with villages that have long depended on coastal resources for survival. That survival has always been relatively easy since coastal regions are home to a rich and varied biodiversity, they have had abundant rain-fed and groundwater resources, and they depended commercially on old trading centres. As the settlement mix changed, and as land use did too, India’s coastal talukas, tehsils and blocks either merged with a creeping mantle of urbanisation or warred with it. Either way, complex coastal ecosystems suffered. 

For those who observe and measure and catalogue our physical coastal world -- the legion of scientists who have long warned us of the biophysical debit that is mounting -- there are a small set of fundamental questions that must be asked every season and answered every season: what are we putting in? What must we find out about, and what should we do with what we find? What problems stand in our way and how do we rid ourselves of these? The answers, iterated before and after every monsoon, with ever-gloomier consequences, are as follows. We who live along the coasts are moving material (nitrogen, phosphorous, wastes) into coastal spaces at rates far greater than nature did. It is in these coastal spaces that nutrients are often recycled (benefiting fisheries). It is because that happens that we need to understand the processes of carbon and nutrient cycling and the national and global significance of coastal seas to the carbon cycle. 

That is why we need to be able to predict the evolution of coastal ecosystems for different change scenarios. When change comes, what will happen to our social and economic activities and how can we improvise strategies for the sustainable management of coastal resources? Finding answers to help us find routes through the problem is far more difficult for our coastal habitats because coastal seas undergo cumulative changes, and because they are a significant part of complex biological systems. Anywhere along our coast, the species are numerous, the numbers are large, and there are different metabolic rates and different impacts of myriad lifecycles. These different biological systems respond slowly, which delays or disguises the ecosystem response. And that is why the overall burden of economic growth on coastal mainland India, of 5,400 km x 50 km, is so poorly understood. And why the response lag is exploited by industry and authorities alike. 

Municipal wastewater constitutes the largest single source of coastal marine pollution. The Central Pollution Control Board estimates that 87 cities and towns located in India’s coastal areas in nine states together emit more than 5.5 billion litres of wastewater per day, which is almost 80% of their total water supply (the estimate in million litres per day, or MLD, which is the measure that water resource and pollution control authorities use, is 5,560.99 MLD). This is a staggering volume of fluid, equivalent to a third of the total quantity of wastewater generated by 644 Class I cities and Class II towns in the entire country. It is also 2.5 times the volume of wastewater (about 2.2 billion litres/day) that the same 87 cities generated two decades ago. Of the 5.5 billion litres/day -- less than a tenth (521.51 MLD) -- is treated to any level before being released into coastal waters. The three states of Maharashtra (45%), West Bengal (26%) and Tamil Nadu (9%) account for the bulk of wastewater flushed into our coastal seas, while about 3.22 billion litres/day of wastewater flow into the Arabian Sea and about 2.33 billion litres/day flow into the Bay of Bengal. 

What is to be done? A first step would be to close the treatment gaps for domestic wastewater and industrial wastewater. Today, for every litre of domestic wastewater in India that is treated and then released, 3.8 litres are left untreated. The ratio for industrial wastewater is marginally better: for every litre cleaned, 1.6 litres are not. However, these are official figures and based on registered usage -- every single urban settlement and its adjoining unregistered micro-enterprise zones survives on water and power theft, and, while electricity leaks are easily detected, water pilferage is not. A more realistic pair of ratios (cleaned:uncleaned) to use for the municipal limits of metropolises therefore would be 1:5 litres for domestic wastewater and 1:2.5 litres for industrial. 

The cost estimates for cleaning up domestic and industrial wastewater may be formidable to the average Class II town municipality, but scaled to a national need, the total capital cost for establishing treatment systems for India’s entire domestic wastewater is placed at around Rs 7,600 crore, which is well under the lifecycle budgets of some of the Bharat Nirman components (operation and maintenance would be in addition, but solutions can be found using service fees for residents). The answer for untreated industrial wastewater is rather more troublesome, for setting up effluent treatment systems to tackle wastewater from small-scale industries runs into the twin problems of space (besides, many small-scale industry estates adjoin residential areas) and funds. One solution lies in common effluent treatment plants, a number of which are running already and show they can reduce the pollution load in aqueous resources. 

This requires local-scale solutions, costs, benefit-sharing, monitoring and empowerment. Which are the districts that place the greatest stress on India’s coastal ecosystems? A framework of indicators of potential coastal vulnerability to development was developed by a team (L Noronha, S Nairy, S Sonak, M Abraham and S Sreekesh) at The Energy and Resources Institute’s (TERI’s) Western Regional Centre in Goa. They presented a framework of indicators of coastal vulnerability to development-related activities in India. The object is to enable policymakers and others involved in coastal management to assess the vulnerability of coastal regions in India and to examine the links between anthropogenic activities and the health of coastal ecosystems. The framework identifies:

  • Key development pressures with the potential to affect coastal ecosystems.
  • Where development driving forces are strongest.
  • Where coastal ecosystems are most affected.
  • Coastal districts that have heavy development pressures as well as stressed ecosystems.

The results list coastal districts in India in order of priority for intensive study aimed at improving coastal planning and suggesting management interventions (see Table). The indicators suggested could be used to design coastal monitoring systems, which can help develop more sophisticated socio-economic and environmental indicators for both west and east coasts.  

Coastal districts under stress
Urbanisation Industrial activity Intensive agriculture/aquaculture Port activity Tourism Rank
Mumbai Mumbai Kheda Mumbai Chennai 1
Chennai Thane Tanjore Chennai Mumbai 2
Mahe Ahmedabad West Godavari Kutch North Goa 3
24 North Parganas Raigad 24 North Parganas Visakhapatnam South Goa 4
Ernakulam Chennai Krishna 24 North Parganas Ernakulam 5
Pondicherry Bharuch Ernakulam South Goa Thiruvananthapuram 6
Kozhikode Vadodara Kottayam Dakshin Kannada Kozhikode 7
Alleppey Surat Chengai Anna Ernakulam Kanyakumari 8
Daman Kheda Alleppey Cuttack Ahmedabad 9
Ahmedabad Valsad Srikakulam Jamnagar Kottayam 10
Thiruvananthapuram Visakhapatnam Vadodara East Godavari Vadodara 11
Trichur Pondicherry East Godavari Raigad Pondicherry 12
Quilon Ratnagiri Surat Ratnagiri Visakhapatnam 13
Yanam 24 South Parganas Pudukkottai North Goa Puri 14
Thane Daman Mednipur Sindhudurg Bhubaneshwar 15
Source: The Energy and Resources Institute (TERI); Indicators of coastal vulnerability. Higher rank indicates greater stress

The TERI group also identified pressure indicators and their significance to the environment: 

  • Persons/sq km (population density) to understand threats from coastal development, sewage, land cover clearance, groundwater depletion, and overexploitation of resources.
  • Density of tourist rooms (tourist infrastructure) to capture the threat to land use and land cover, groundwater depletion, water and beach pollution from recreational activities.
  • Area under intensive aquaculture to find threats to mangrove clearance, land use change (agriculture), saline intrusion into coastal aquifers, eutrophication, threats to wildstock.
  • Fertiliser use/ha, cultivated area, irrigated area to assess potential threats of eutrophication, groundwater depletion, soil degradation, and land cover change.
  • Number of potentially polluting industrial units located determines threats from industrial pollution, land cover change, and groundwater depletion.
  • Total cargo handled at ports measures potential threats from oil spills and impacts on marine life; from species introduction through release of ballast water and need for port extension and consequent impact on marine life.

Following the release of the National Action Plan for Climate Change in 2008, the additional factor of climate change vulnerability of coastal districts and their populations is gradually gaining acceptance. Such recognition has come late, but Centre, state and particularly local self-governments will have to act urgently to find their footing. Changes in temperature and precipitation will have a direct impact on demand and supply of energy, and the quantity and quality of water available for irrigation, hydropower, and domestic and industrial use. A change in rainfall patterns could lead to intense and short-lived precipitation in coastal urban watersheds (as we have seen from 2004 onwards, and in Mumbai 2005) which would lead to calamitous flooding. When accompanied by sea level rise -- a consequence of climate change -- excessive flooding of urban settlements and industrial zones is a certainty, endangering the lives of tens of millions and threatening infrastructure. This is especially so where drainage infrastructure is poorly designed and maintained, which is the case in most of these cities and towns right now. In addition, because appropriate urban development planning and land use zoning is not practised or is politically suppressed in most cities and towns in India, residential areas are mixed with commercial and industrial units. The combination of sea level rise, calamitous flooding, chronic wastewater pollution and stressed public health systems poses a severe threat to coastal populations. The response -- guided by frameworks such as the TERI attempt -- is for coastal urban and local government authorities to legislate adaptation measures as quickly as possible. 

What are the chances that this understanding will be embedded into urban and local coastal administrations in time? On paper, central government agencies are promoting a strategy that combines climate change efforts with the broader development and poverty reduction agenda to foster more climate-resilient and sustainable economies. One recent indication comes from the Parliamentary Standing Committee on Science and Technology, Environment and Forests report on Coastal Management Programmes, which was presented to the Rajya Sabha on March 20, 2009. It deals mainly with the proposed Coastal Management Zone (CMZ) notification, which was designed to replace the 1991 Coastal Regulation Zone (CRZ) notification but was dropped in July 2009 by the government due to opposition from fishermen and their organisations. In the report, the aspect of community ownership of resources and the need to strictly control use of the coastal zone are emphasised. “The basic rights and opportunities for the local communities or their representatives (panchayat members) to participate and plan the activities in their local environment and settlement areas are highly curtailed in the proposed Integrated Coastal Zone Management Plan (ICZMP) process,” states the report. 

It goes on to add that the roles of public authorities and of government departments (such as fisheries, environment, municipal corporation and block development office) need better definition. “The concepts like ‘setback line’, ‘ecologically sensitive area’, ‘integrated coastal zone management’ mentioned in the CMZ notification, 2008, are vague and are open to subjective interpretations. Hence clarity is required on these aspects,” the report says. In view of the local-needs-versus-national-policy conflict, the report is clear and direct: “The committee is of the view that a common management plan for the entire coastal area of the country is not a workable proposition. It feels that it should rather be specifically designed for different states keeping in mind the diverse coastal environments and specific cultures of coastal communities.” 

How will the new claimants to India’s coasts react to the emerging official line (even if this new line is a subjective guideline)? The answer lies with the state governments that have encouraged ‘notified industrial estates’, special economic zones, greenfield airports, new gas-based power plants with LNG jetties attached, and that have permitted the conversion of hectare after hectare of agricultural land to commercial or settlement to favour the property development industry. It lies also with the many panchayats which have organised themselves -- often in the teeth of state-sponsored opposition -- to examine and reject such takeovers, and whose communities have been traditionally linked to the sea as original stewards and protectors of our coasts.  

India’s watery waste footprint 

Fifteen locations that degrade our coastal ecosystems with untreated effluents thick with metals and chemicals, and raw sewage

From 2006, the Ministry of Earth Sciences has monitored marine pollution through the Coastal Ocean Monitoring And Prediction System (COMAPS) programme. This programme has, for the first time, measured the wastes from settlement zones, industrial zones and coastal aquaculture that flow into our coastal waters near major urban centres. The results so far are an eye-opener. Each one of the 19 coastal locations monitored and mapped shows how the health of our coastal ecosystems is being steadily degraded by currents of untreated effluents thick with metals and chemicals, and torrents of raw sewage. Here are the assessments of the 15 main COMAPS stations, starting from West Bengal and moving counter-clockwise round the coast to Gujarat: 

Hooghly: The Hooghly river at its mouth receives domestic sewage which is mostly treated in Kolkata, and untreated sewage from a number of villages along its banks. As a result of sewage disposal, wastewater contains mostly bacteria, nutrients and putrefied organic compounds. A number of industries discharge their waste directly into the Hooghly estuary. These industries manufacture products like chemicals, pesticides, fertilisers, pharmaceuticals, synthetic fibre, engineering, etc. The total wastewater generated from these industries is around 7 MLD (million litres per day, or 7,000 cubic metres), and is discharged mostly treated. 

Paradip: A port town on the Orissa coast. It has a population of about 75,000 and generates 6.6 MLD of sewage, all of which is discharged untreated into the coastal waters. There are two major industries here: Paradip Phosphates and Oswal Chemicals and Fertilisers. Paradip Phosphates discharges 8,900 m3/day of treated wastewater into the coastal waters through creeks. The major pollutant is phosphate. Oswal Chemicals and Fertilisers does not discharge wastewater; it is reported to be recycled within the plant. Industrial wastewater and municipal sewage discharged into coastal waters have high biological oxygen demand (BOD) and bacteria levels. 

Visakhapatnam: A port city hosting industries like steel mills, engineering, chemicals, fertilisers, petroleum, and a thermal power plant. India’s largest shipbuilding yard and port are located here. The population of Vizag city is around 1.3 million. The steel plant discharges its effluents into a creek which empties into the Bay of Bengal. About 68 MLD of sewage is generated and about 55 MLD is discharged through the Mehalingatta, which drains into Visakhapatnam harbour. As a result of multiple industrial discharges, which are mostly treated, the coastal waters receive a combination of untreated sewage and treated industrial waste. Near Visakhapatnam is Gangavaram, a fast-developing port town with a steel plant and thermal power plant. It is likely to attract several industries. 

Kakinada: A port town with industries like fertilisers and petrochemicals. There are two large fertiliser plants and one gas-based power plant here. Kakinada has a deep-water port and a population of around 0.45 million of which about 0.2 million depend on fishing for their livelihood. Agriculture and aquaculture are other major sectors. Reliance Industries, which is extracting gas from the Krishna-Godavari basin, has built a gas-receiving jetty. Kakinada bay is bordered on the south by Coringa mangroves which are ecologically sensitive. Kakinada canal, through which the town’s sewage enters the bay, is the major source of organic pollution. 

Bhimavaram: Bhimavaram town, with a population of around 0.13 million, is located about 20 km from the Bay of Bengal. Aquaculture is a major livelihood activity and fish farms operate between Bhimavaram and the coast. Agriculture is the next major sector. A few industries are located in the vicinity of Bhimavaram. Discharge of untreated sewage by civic bodies and effluents by industry is cause for concern. The wastewater from aquaculture farms contains high concentrations of nutrients, toxic chemicals and antibiotics. 

Ennore: On the outskirts of Chennai city, Ennore hosts a variety of industries: pharmaceuticals, engineering, fertilisers, lead, rare earth, and two thermal power plants. The total wastewater released by industries other than power plants is 28 MLD. The two power plants discharge about 100 MLD of coolant water into the sea through the Ennore creek. The coastal waters off Ennore also receive untreated sewage through marine outfall close to the shore. As a result of multiple industrial discharges, the coastal waters receive a combination of untreated sewage and treated industrial waste. Domestic sewage predominantly contains BOD compounds, nutrients and bacteria. 

Pondicherry: Pondicherry has a population of around 0.75 million and generates wastewater of about 45 MLD, with the entire amount discharged untreated into the sea through backwaters and creeks. Pondicherry hosts major industries like paper, alcoholic beverages, chemicals and pharmaceuticals. The total treated wastewater discharged from industries is about 7 MLD. Wastewater from sewage contains mostly BOD compounds, nutrients and bacteria. Industrial wastewater mainly contains suspended matter, BOD compounds and trace amounts of oil and gas. 

Cuddalore: With a population of around 0.3 million, this town generates about 13 MLD of sewage. All this, in untreated form, is disposed of in the Ponnayar river which empties into coastal waters. Near Cuddalore is SIPCOT, an industrial zone that houses a variety of industries manufacturing paints, pharmaceuticals, chemicals, agro-chemicals, agro-food, ceramics, engineering, plastics, textiles and PVC. These industries release approximately 7.5 MLD of mostly treated wastewater into the backwaters that empty into the sea. The raw sewage contains high BOD compounds such as putrefied organic matter (kitchen and toilet waste), nutrients and bacteria. 

Tuticorin: A port town with several industries and saltpan activity, its population is around 0.4 million. The town generates an estimated 17.5 MLD of sewage. There are no treatment facilities for the sewage; all of it is disposed of in canals that eventually reach the sea. Industries around Tuticorin include a refinery, aquaculture, chemicals and fertilisers, caustic soda and a thermal power plant. The total volume of waste discharge from these industries, other than aquaculture, is about 10.4 MLD. The effluent characteristics from these industries include suspended solids, ammonia, nitrate, BOD compounds, oil and grease, and trace quantities of heavy metals such as chromium. Aquaculture generates about 91.2 MLD. Municipal waste contains high BOD compounds (putrefied organic matter), nutrients and bacteria. 

Kochi: A heavily populated city located along backwaters that receive effluents from upstream industries including fertiliser plants. Kochi’s population is around 0.6 million and the amount of sewage generated is about 36 MLD. The backwaters do not experience strong tidal action and therefore seawater that can dilute pollutants is limited. However, heavy rainfall causes flooding during the monsoon months which serves to dilute pollutants from June to September. 

Mangalore: A coastal city in Karnataka with a population of 0.5 million. This is not a heavily industrial area, except for a refinery, a few medium- and small-scale industries and the Kudremukh iron ore handling facility. The coastal waters experience intensive fishing activity; a large number of fishing vessels are berthed in the fishing port. Sewage of about 28 MLD is released into the Netravathi and Gurupur rivers which reach coastal waters. 

Goa: Has a population of around 1.3 million and few industries are located near coastal areas. A major source of pollution of the Mandovi and Zuari rivers is the release of untreated domestic sewage. The Zuari Agro Chemicals plant releases effluents into coastal waters. Mining of iron and manganese ore occur on a large scale in the upper reaches of the Mandovi and Zuari rivers; mining wastes containing iron in suspended matter empty into coastal waters mostly during the monsoon, through canals. 

Thane creek: A variety of industries, including a chloralkali plant, release their effluents into the creek which runs into the sea. There are about 140 large-scale industries, around 125 medium-scale industries, and around 1,600 small-scale industries in Thane district. Most of these industries generate wastewater which is released into Thane creek with or without treatment. The large-scale industries are believed to treat effluents whereas the medium- and small-scale industries dispose of untreated waste, mostly effluents, into Thane creek. Some efforts are being made to set up a common effluent treatment plant for treatment of effluents from medium- and small-scale industries. Besides, domestic sewage also enters Thane creek from sewage/open drains surrounding the creek. The spring tidal range of 4.2 m-5 m is prevalent at the mouth of Thane creek, diluting effluents. 

Mahim, Versova and Bassein (Mumbai): Mahim bay receives sewage from point sources collected by sewers from residential areas. Waste from a variety of industries located along the banks also reaches the bay. The total sewage load of Mahim bay is about 830 MLD, and industrial effluents about 93 MLD. As a result of heavy inflow of sewage, which contains mostly organic waste, water quality is seriously degraded especially during the non-monsoon months. The near shore waters of Versova receive 440 MLD of sewage. There are hardly any industrial sources of pollution in this area and the sewage is released after primary treatment. Bassein receives domestic effluents through the Ulhas river, and industrial effluents from the Kalyan-Ulhasnagar-Ambernath belt which supports 79 large-scale industries, 55 medium-scale industries, and 92 small-scale industries. All these release their effluents into the Ulhas river. The amount of sewage received by the river is estimated to be 730 MLD. 

Hazira: Located at the mouth of the Tapi estuary in Gujarat which carries domestic and industrial waste from Surat city and the suburbs. The Hazira-Kawas industrial belt is home to petrochemical, fertiliser, steel, engineering and power industries together estimated to release 60 MLD of effluents. The LNG terminal is also located at the mouth of the estuary. Surat has a population of around 0.35 million and is estimated to release about 300 MLD of sewage, mostly untreated, into the Tapi estuary, which finally reaches Hazira point.   

(Institutions participating in COMAPS are: Institute of Minerals and Materials Technology, Bhubaneswar; Department of Marine Biology, Annamalai University; Centre for Earth Science Studies, Thiruvananthapuram; National Institute of Oceanography, Goa; and Regional Centre, National Institute of Oceanography, Mumbai) 

(Rahul Goswami is an independent journalist based in Goa)

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