Key Drivers of Water Pollution

Almost 70 per cent of India’s surface water resources and a growing percentage of its groundwater reserves are contaminated by biological, toxic organic and inorganic pollutants. In many cases, these sources have been rendered unsafe for human consumption as well as for other activities such as irrigation and industrial needs. The high incidence of severe contamination near urban areas indicates that the industrial and domestic sector’s contribution to water pollution is much higher. Besides rapidly depleting groundwater table, the country faces another major problem on the water front – groundwater contamination – a problem which has affected as many as 19 states, including Delhi. The geogenic contaminants, including salinity, iron, fluoride and arsenic have affected groundwater in over 200 districts spread across 19 states.

Driver of water pollution

Fertilizers

Rapid increase in agro-chemical use in the past five decades, has contributed significantly to the pollution of both surface and groundwater resources. Fertilizers and pesticides enter the water supply through run-offs and leaching into the groundwater table and pose a hazard.

• Some of these substances have been known to bio-accumulate in certain organisms, leading to an increased risk of contamination when used for human consumption and a persistence of the chemicals in the environment over long periods of time.
• Water enriched with nutrients leads to eutrophication. Decaying organic matter releases odourous gases and partially decomposed matter accumulates on the river or lakebed, thereby limiting water’s suitability for human consumption and other uses.
• High levels of fertilizer use has been associated with increased incidence of eutrophication in rivers and lakes in several of India’s most important water bodies.

Industrial Sector

Though Industrial sector only accounts for three per cent of the annual water withdrawals in India, yet its contribution to water pollution, particularly in urban areas, is considerable. Wastewater generation from this sector has been estimated to be 55,000 million m³ per day, of which 68.5 million m³ are dumped directly into local rivers and streams without prior treatment. The government has called for the establishment of Common Effluent Treatment Plants (CETP) in industrial areas but their implementation has been slow, and most industries either are not connected to CETPs or only partially treat their wastewater before disposal.

Domestic Sector

The domestic sector is responsible for the majority of wastewater generation in India. Combined, the 22 largest cities in the country produce over 7,267 million litres of domestic wastewater per day, of which slightly over 80 per cent is collected for treatment. Inadequate treatment of human and animal wastes also contributes to high incidence of water-related diseases in the country. Till date, only 19.2 per cent of the rural and 70 per cent of the urban inhabitants have access to adequate sanitation facilities.