Soil pollution relates to chemical degradation of soil that includes acidification, declining fertility, changes in the pH level, salinisation, and chemical toxicity. For India, maximum
soil contamination occurs in agricultural land, wastelands, and in urban areas.
Rural agricultural sector
In India, 291 registered source chemicals are used to formulate fertilisers. About 577 registered fertilisers have been identified to be harmful for the environment. Their use leads to polluting of both ground water and surface water along with soil pollution. The country has already banned the use of dichloro-diphenyl-trichloroethane (DDT) - a pesticide - as it leads to agricultural pollution. An organic shift can decrease the pollution level, but the soil productivity decreases. Therefore, chemical fertilisers continue to be used to meet
Many unaware farmers continue to use unnecessary amounts of boron, zinc and molybdenum fertilisers to increase productivity and contribute to soil pollution. Dr Sushanta Kumar Pal,
Professor and Head of the Department, Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, informed BE, “To create awareness among farmers, the central government has initiated the ‘Soil Health Card Scheme’ that will carry crop-wise recommendations of nutrients and fertilisers required to improve productivity of different
yields. Various state governments through their agriculture development offices are also testing the requirements of the fertilisers for different soil types in their laboratories, which is
expected to minimise the soil pollution level. Additionally, we are recommending organic farming where possible.”
The Green Revolution that helped the Indian agricultural sector to substantially increase production - mostly in the northwestern states - also had some detrimental environmental impacts. It pioneered the adoption of new technologies including High Yielding Variety (HYV) seeds, increased usage of chemical fertilisers, and agro-chemicals. Professor Pal said, “Since the Green Revolution, states like Punjab and Haryana have been indiscriminately using chemical fertilisers – often twice the national average. Vegetable planters, in many cases, believe the soil lack necessary micronutrients for a healthy yield and they are prone
to use more nitrogenous and phosphorous fertilisers, which are leaching to deeper layers of the soil and contaminating the drinking water level. South Indian states are also prone to use
excessive fertilisers. But states like West Bengal and Bihar are using comparatively less chemical fertilisers.”
During 2015, the estimated sewage generation in the country was around 61,754 million litres per day (MLD) as against the developed sewage treatment capacity of around 22,963 MLD. Due to lack of adequate sewage treatment capacity, about 38,791 MLD of untreated sewage -about 62% of the total generated sewage - is directly discharged into water. Additionally, about 13,468 MLD of wastewater is generated by largescale industries in India which disturbs the irrigational network in India.
Impacts on ground water
Poor soil and water management are majorly responsible for soil contamination. In industrial clusters of the country, groundwater salinity is increasing rapidly. According to agricultural experts, groundwater pollution has adversely affected the cropping pattern and crop yield in India. As India has irregular allocation of rainwater, the country overtly depends on groundwater and surface water for crop production.
A Food and Agriculture Organisation (FAO) report of 2017 titled ‘Status of Soil Pollution in India’ informs, “Onion grown using polluted groundwater had a short keeping quality and started rotting within 10–15 days after harvest; thus inflicting heavy economic losses to the farmers.”
In India about 140 million people are expected to move to urban areas by 2020 and another 700 million by 2050. The waste produced in urban areas of India is approximately 1,70,000
tonne per day, which is equivalent to about 62 million tonnes per year. The figure is expected to increase every year by 5%. In this situation, unplanned urbanisation, irregular waste management by the government and polluting industries is leading the country towards a catastrophic situation. Certain cities are undertaking unplanned landfills with plastic and
e-wastes without thermo-chemical processes of sorting. The most problematic is small pieces of plastic - sized between 2 mm and 5 mm – which are scattered all around.
A report titled ‘Waste Management Initiatives in India for Human Well Being’ by the European Scientific Journal states, “In India, new and expensive technologies are being pushed to deal with the urban waste problem, ignoring their environmental and social implications. It is particularly true in the case of thermal treatment of waste using technologies such as gasification, incineration, pyrolysis or palletisation.” Inadequate mechanism, absence of green-technologies and lacking segregation-at-source procedures have increased the intensity of the problem in India. Apart from governmental agencies, civil society actors are trying to combat the situation. The Public-private-partnership (PPP) model can be useful way to mitigate this crisis. The Greater Chennai Corporation and Onyx – a French multinational – had partnered for garbage collection in Chennai.
Industries including chlorine-alkali, textiles, glass, rubber production, animal hide processing and leather tanning, metal processing, pharmaceuticals, oil and gas drilling, colour manufacturing, ceramic manufacturing, soap and detergent production are the major consumers of sodium chloride. Industrial effluents from these industries are major sources of pollution.
India is having many polluting industries. The Central Pollution Control Board (CPCB) on March 13, 2020 published a report stating that 700 industries were highly polluting while 342 industries were found non-compliant to the environmental norms.
Major industrial-hazardous areas in India
The Nagda industrial area in Madhya Pradesh has many effluents like viscous rayon, caustic soda, liquid chlorine and carbon disulphide which are carried away naturally to the Chambal river. The same cycle is replicated in the Ratlam industrial area in Madhya Pradesh near the
Mahi River. The Patancheru industrial area in Andhra Pradesh is also one of the highest polluting bulk drug manufacturing areas in India. The zinc smelting area in Rajasthan is also highly polluting. The Pali textile industrial belt in Rajasthan having more than 800 textile units discharge printing and dyeing effluents into the Bandi river. The Katedan industrial
development area in Andhra Pradesh, the Thane industrial region and the Vellore tanneries are also some of the most polluting areas in India.