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Industrial pollution poses a serious problem for our planet and the threat is particularly imminent for rapidly industrialising developing nations such as India and China. Industrial waste has been recognised as a major cause of pollution globally and there is an urgent need to identify polluting industries and roll out policies to control their pollution. To put the problem in perspective, management of industrial pollution in developing economies poses several challenges as industrialisation is intricately linked to economic growth and employment generation. Often the environmental agencies are ill-equipped to handle polluting emissions and industrial by-products. of industries. 

India and the world

Drawing on measurements and calculations, as of 2016, from air monitoring stations in 4,300 cities, the World Health Organisation (WHO) reported in March that Indian cities suffer the most. Kanpur with a population of three million tops the list with a yearly average of 319 micrograms per cubic metre of PM2.5, the most hazardous particle commonly measured.

The WHO does not treat its data as a ranking but rather as a measurement of risks. But it is clear from the report that India is one of the riskiest countries in the world to breathe along with Bangladesh and Georgia. When it comes to comparing PM10 measurements of the world’s largest cities, India’s capital Delhi comes with an annual average of 292, ahead of Cairo (284), Dhaka (147), Mumbai (104), and Beijing (92).

Over half of India's population – 660 million people – live in areas where the presence of fine particulate matter pollution is above India's recognised safety standards, said a study done by economists from the University of Chicago, Harvard and Yale and published recently in the   ‘Economic & Political Weekly.’

Of the world’s top 20 polluted cities, 13 are in India compared to just three in China. Air pollution slashes life expectancy by 3.2 years for the 660 million Indians who live in cities, including Delhi. In China, the corresponding dip is marginally lower at three years.

Polluting industries in India

The Ministry of Environment, Forest and Climate Change in consultation with Central Pollution Control Board has classified industries into “Red”, “Orange”, “Green” and “White” categories, according to their polluting levels. The Pollution Index (PI) of any industrial sector ranges from 0 to 100. The increasing value of PI denotes the increasing degree of pollution load from the industrial sector. Industrial sectors having PI score of 60 and above are under the ‘Red’ category. Industrial sectors having PI score of 41 to 59 are under the ‘Orange’ category. Those having PI score of 21 to 40 is under the ‘Green’ category and PI score including and up to 20 fall in the non-polluting ‘White’ category.

The Central Pollution Board (CPCB) has identified 17 categories of most polluting industries which contribute to the environment in terms of suspended particulate matter, gases and effluents. About 77% of the industries contribute to water pollution while 15% contribute to air pollution and the remaining 8% contribute to both air and water pollution. The industries which are dependent on natural resources are the most polluting ones and are growing rapidly. Heavy metal pollution from industries is affecting human health.  Let us look into the highly polluting industries in India.

Aluminium, Copper and Zinc Smelting

The principal sources of pollution caused by smelting are contaminant laden air emissions and process wastes such as wastewater and slag. Lead, arsenic, selenium and particulate matter from copper smelters contaminate people living downwind and downstream. Sulphur dioxide emissions can cause acid rain, although the impact on weather patterns is more complex. Organic vapors and sulphur oxides resulting from smelting roasting operations and fuel combustion can cause smog containing polluting elements like fine airborne particles, nitrogen oxides, sulphur dioxide and carbon monoxide.

Basic Drugs and Pharmaceuticals Manufacturing

Samples taken from sewers and other sites around bulk drug manufacturing plants in Hyderabad showed disturbingly high levels of antimicrobial substances. 95% of the samples contained multidrug-resistant bacterial strains.

Chlor Alkali/ Caustic Soda Manufacturing

The major waste stream from the process consists of brine muds which is the sludge from the brine purification step. It contains magnesium, calcium, iron, and other metal hydroxides, depending on the source and purity of the brines.

Cement

The direct emissions from the cement industry occur through a chemical process called calcination.  The main pollutants emitted from cement industries include Particulate Matter, Sulphur Dioxide (SO2) and Nitrogen Dioxide (NO2). This single industry accounts for around 5% of global Carbon Dioxide (CO2) emissions.

Fertiliser and Pesticide Formulation and Manufacturing

The effluents from the chemical fertilizer industry contain organics, nitrates, alcohols, ammonia, phosphorous, heavy metals such as cadmium and suspended solids and are responsible for water and soil pollution. The largest threat from pesticide manufacturing and storage is caused by old and improper storage containers and facilities that allow concentrated levels of toxins to leak into the environment.

Integrated Iron and Steel

Iron and steel industries have been concerned with emissions from their furnaces and cupolas. Air-polluting emissions from steelmaking furnaces include metal oxides, smoke, fumes, and dusts. Steel-making is commonly associated with coke ovens. Coke oven emissions are complex mixtures of gases, liquids, and solids notably formaldehyde, acrolein, aliphatic aldehydes, ammonia, carbon monoxide, nitrogen oxides, phenol, cadmium, arsenic and mercury.

Leather Processing including Tanneries

Leather has the greatest impact on eutrophication, a serious ecological problem in which runoff waste creates an overgrowth of plant life in water systems, which suffocates animals by depleting oxygen levels in water.

Oil Refinery

The combustion process of petroleum, coal and wood is responsible for increased occurrence of acid rain. Combustion causes an increased amount of nitrous oxides. Release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, is a form of pollution and can be linked to oil refineries. Spilt oil penetrates into the structural plumage of birds and the fur of mammals, reducing its insulating ability and making them more vulnerable to temperature fluctuations and less buoyant in the water.

Pulp and Paper

The waste water from these industries is laden with various toxic chemicals like Volatile Organic Compounds (VOCs) such as terpenes, alcohols, phenols, methanol, acetone, chloroform, methyl ethyl ketone; detergents and surfactants; dyes and pigments; acids; and alkaline solutions.The effluent is rich in thiols, sulfur dioxide, sulfites and sulfides. The waste water is also inclusive of bleaching agents such as hydrogen peroxide, chlorine dioxide and caustic soda. Other pollutants include whitening agents such as kaolin, calcium carbonate, talc and titanium dioxide.

Sugar

Large amount of waste is generated during the manufacture of sugar. It contains a high amount of suspended solids, organic matters, effluent, sludge, press mud and bagasse. Higher values of these parameters in ground water indicate industrial pollution.

Thermal Power Plants

The gases emitted from thermal power plants are highly polluting. It contains carbon dioxide, nitrogen oxides, sulfur oxides, mercury and traces of other metals. 

Governmental Initiatives

The present Union government has decided that the country’s most-polluting industries will need consent to operate after every five years, doing away with a UPA-era annual-approval clause that also looked at the impact on health and biodiversity. With this step, the Narendra Modi government has overhauled a regulation introduced by former environment minister Jairam Ramesh that was based on the effect of industrial clusters on air, water, land, health and ecology. Based on the Comprehensive Environmental Assessment of Industrial Clusters (CEPI) ranking system, Ramesh had imposed a ban on allowing new industries in several regions, including Vapi and Ankleshwar in Gujarat. However, in the revamped CEPI, a ban on new industries will be the exception rather than the rule. In a major relief to industries, the government has decided that the approval to operate will be valid for five years in case of the most-polluting red category units, 10 years for the slightly less-polluting orange category, and the cleaner green category units will require one-time approval. 

“We are doing away with the annual consent so the industry owners don’t have to visit government offices again and again,” said environment minister Prakash Javadekar, adding that the categorisation of over 10,000 industries was being re-worked on the basis of overall pollution potential instead of size and effluent discharge.