Air, a mechanical mixture of different atmospheric gases, is the life blood of man. One may survive for a few days without water or for few weeks without food, but without air one's life can hardly last for a few minutes. A normal human being requires- about 35 gallons or 16 kg of air each day which he obtains from the oxygen rich atmosphere surrounding the earth.
Burning huge quantity of fossil fuels, cutting forests and reducing ocean planktons by pesticides and oil spills have not only affected the proportion of atmospheric gases, but have left out thousands of tons of solid wastes in the form of dust, smoke and toxicant matters in the form of atmospheric impurities.
The chief pollutants of air are carbon monoxide, sculpture dioxide, nitrogen oxide, certain hydro carbons and particulate matter (Ambasht, 1978). All these pollutants arise specifically from exhaust emission from motor vehicles, aero planes and chimneys of factories. They are more dangerous in combination and sometimes produce smog in industrialized areas blanketing the sunlight or leading to acid rains.
Air pollution in India has assumed alarming proportion due to rapid pace of industrialization and urbanization, particularly after Independence. The metropolitan cities of the country are injecting huge quantity of pollutants into the atmosphere. In fact, there level is approaching the cities of developed countries.
According to the World Health Organisation (WHO) the level of air pollution in Delhi has crossed the human endurance level. According to an estimate here 64 per cent of the air pollution is caused by automobiles, followed by thermal power plants (16%), industry (12%) and domestic sector (8%). Delhi has over three million vehicles on its roads which are more than the total number of vehicles in Mumbai, Kolkata and Chennai.
The number is increasing at a rate of over one lakh per year. These vehicles spew daily 1,063 tons of carbon monoxide, 400 tones of hydrocarbons, 323 tones of nitrogen dioxide, and 179 tones of sculpture dioxide, 600 kg of lead and large quantities of suspended particulate matter (SPM). A number of vehicles from the neighbouring states of Uttar Pradesh, Haryana, Punjab, Rajasthan, Uttaranchal etc. daily enter the city and add to its pollution load. Thermal power plants of Indraprastha, Badarpur and Rajghat emit over one thousand tons of ash and dust.
Industrial units in and around the localities of Lawrence road, Wazirpur, Najafgarh road, Kirti Nagar, DLF industrial area and Moti Nagar etc. discharge huge quantity of air pollutants like S02, dust and other particulates. The slums and city garbage also aggravate the problem in congested areas of the old city.
Mumbai is another highly polluted city of the country. Its air is being polluted at the rate of 6,000 tons of pollutants per day from various sources. About 52 per cent of the total pollution load is contributed by automobiles. About 48 per cent of S02 emissions come from industries and 33 per cent from power plants.
The belt between Chembur and Trombay is highly industrialised and has 3 to 6 times more pollution than rest of the city. About 2,000 tons of pollutants are added to the atmosphere every day in the Trans-Thane Creek industrial area which has the highest concentration of chemical industries in the country.
Most of them are linked to the petroleum industry. Tarapur atomic power plant continues to spew out dangerous radiation doses. Besides, noxious fumes emanating from garbage dumps has also become a cause of great concern in the city. More than 60 per cent of the people in Ghatkopar and Chembur suffer from various ailments caused by the noxious fumes from the burning of garbage at Deonar dumping ground.
The air pollution problem of Kolkata is' more serious because of less availability of open space for diffusion of air pollutants. According to the report of the National Environmental Engineering Research Institute (NEERI, Nagpur, 1981) 1.305 tons of pollutants are daily injected into the atmosphere of the metropolis. Of these, industries contribute 600 tons; transport 360 tons, thermal power plants 195 tons and domestic source 50tonnes.
The main pollutants of the air of the metropolitan district are suspended particulates (560 tons), carbon monoxide (450 tons), sculpture dioxide (125 tons), hydrocarbon monoxide (450 tons), sculpture dioxide (125 tons), hydrocarbons (102 tons) and nitrogen oxide (70 tons). The industrial air pollutants are emitted through 1800 industrial units (1981).
The average SPM level has increased from 237 ug/ cm in 1990 to 354.3 ug/cm in 1995 (CPCB, New Delhi, 1995). About 30 per cent of the total pollution load in Kolkata comes from vehicles, according to the CPCB. In 1996, it was reported that the volume of CO in the city's atmosphere had exceeded all previous limits. The domestic pollutants are produced from 1.200 tons of coal used per day in domestic 'chulhas' (ovens).
Among the metropolitan cities, Chennai seems to have cleaner air. However, experts warn that SPM in many locations of the city is a cause of concern. According to a study conducted during May-July, 1995 it has exceeded the safe limits in Anna Salai, Stanley Medical College Hospital and the Alwarpet and Tirumangalam junctions. The report indicates that vehicular emissions are largely responsible for high SPM levels in these localities.
In the industrial city of Sural the average suspended particulate matter (SPM) emitted from industries and vehicles amounts to 934 microgram per cubic meter of air per day (V.S. Gupta et al" 1983). Here daily discharge of sculpture dioxide, nitrogen oxide, and hydrogen sulphide is recorded as 20, 4, 24.6 and 0.5 micrograms per cubic meter of air respectively, the dust concentration varies from 2 to 23 mg/m1 and oxides of nitrogen from 0.2 to 8.0 p.m. against the threshold limit of 10 mg/m1 and 5 p.m. respectively.
Pollution is not only confined to the large cities of India. Instead it is gripping over the small cities and towns due to haphazard urban and industrial growth, lack of pollution control devices and non-enforcement of pollution control laws,
Kota is fast becoming like Delhi in matters of pollution, the town is known for stone mining, mineral-based industries, cement factories, fertiliser and chemical units and plants that produce synthetic fibers, textile and rayon. A number of polluting units have been closed clown following a Supreme Court order but 35 large and medium scale and about 5,000 small-scale units are still working. Although with the adoption of pollution control measures and processes like reuse of waste, industrial pollution has been minimised but the vehicular pollution is increasing.
This has led to increase in the levels of NOx and S02. Between 1976 and 1998. Almost 1.8 million vehicles were registered in Kota-76.7 per cent of them were two-wheelers with two-stroke engine. Diesel vehicles constitute 16.38 percent of the total count. The city is also teeming with diesel- powered three-wheelers called tempos. Besides, about 2000 vehicles pass along NH 12 every day that goes right through the heart of the city. Due to air pollution, the incidence of chronic diseases is very high in Kota. The lead content in the ambient air is also very high.
In Jaipur city, there is no major air polluting industrial units. The main culprit of air pollution is vehicles. The vehicular population in the capital city has increased six times between 1980-81 and 1998- 99 from 81,267 to 544,556. The total population load on account of vehicular pollution is estimated to be around 280 tonnes per day in Jaipur.
According to CPCB data, the maximum SPM level in the city in 1997 was almost three times the permissible limit, with the maximum level of NOx exceeding the permissible limit at 108 ug/m3, with the ban of Vikrams by the Jaipur High Court in 1996 there is some improvement in the scenario. But most of these banned vehicles are plying on rural and semi-urban route.
In Dehradun, the capital of Uttaranchal, thick blue smoke envelopes the town during winter months. Doon is a broad valley which sometimes gives rise to a lateral inversion that does not allow hot air to rise from the valley. Earlier limestone mining in the neighbourhood was the cause of air pollution which was banned by the Supreme Court in 1986, Today, vehicular emissions are the main reason for air pollution, Presently more than 126,452 vehicles are plying on the roads of the city of which more than I lakh are two-wheelers, Air pollution is concentrated in the middle of the town due to narrow roads and traffic congestion, The Saharanpur road, Gondhi road and the railway station areas are the most polluted areas of the city.
The study has shown that abnormally high levels of SPM in Dehradun are mainly due to natural dust and particulate-laden smoke from diesel-fueled vehicles, especially Vikrams, trucks, buses and three-wheelers. It has been found that the growth of the bougainvillea, lantana, litchi and mango was severely affected by air pollution (Down to Earth, 31.10.1999, p. 39).
The quality of the air of Kanpurcity has been quite bad with maximum SPM level clocking well over 1,000 ug/m\ Air monitoring data for 1997 reveals a strange phenomenon: pollution levels are higher in residential areas as compared to industrial areas. This makes it clear that vehicular exhaust, particularly from Vikrams, contributes significantly to air pollution in this amazingly congested city. The city of 2.7 million people has about 3, 50,000 vehicles.
There are over 4,400 registered and 3,000 unregistered Vikrams plying on the roads. CPCB data show that vehicles release a colossal 3.55 tons of pollutants in the city's air every hour. Traffic congestion, particularly at railway level crossing, is a significant cause of air pollution.
The city burns an unbelievable 300 tons of coal, kerosene, LPG, wood and other fuels every day. The result is the daily emission of about 850 kg of particulate matter; I tone of S02, 600 kg NOx and 3,500 kg of CO. About 75 large-medium and 5,457 small scale industrial units do not lag behind. Major polluters include the thermal power plant and fertiliser units in the Panki industrial area. Air pollution has led to phenomenal increase in the incidence of bronchial asthma, chronic obstructive pulmonary disease and lung cancer in the city.
Air pollution is a grave problem in Lucknow, the capital of Uttar Pradesh. Here SPM level has risen up to 2,339 tig in 1997 (cf, 254 ug/m3 in 1992). In the absence of major industrial units, vehicular emissions account for most of the air pollution. There is no regulated public transport system and the city has about 4, 00,000 vehicles which include 7,500 Vikrams. With the High Court order this diesel powered Vikrams are being replaced with battery-driven ones which may help in bringing down the level of air pollution in the city,
Cinjraula a small town in Moraclabad district, is a victim of industrial pollution, was declared an industrial town in 1981-82 and within a few years a number of industrial units-mainly chemical and pharmaceutical factories-sprung up. After the setting up of these units, air pollution has increased at an alarming rate. CPCB officials in Delhi reveal that of the 20 large and medium-scale industrial units in the town, nine are classified as polluting.
The health of the residents is in jeopardy. There has been steep rise in prevalence of asthma, respiratory problems and lung diseases after the industries have come up. Mango orchards are being affected by air pollution and these are being replaced by sugarcane and rice fields.
The traditional life style of the people in rural areas of India also adds to the problem of air pollution. The open fields used as toilet, open drains, open manure pits near the residences, open disposal of the dead bodies of the domestic animals are a few examples to throw light on the situation.
The kitchens are generally housed in unventilated rooms where traditional Chulhas (ovens) emit large quantities of smoke and harmful gases like carbon monoxide, carbon dioxide, sculpture etc. According to an estimate about 100 million tons of fire wood is burnt which generate 3.14 million tons of particulate matter, 2.35 million tons of hydrocarbons, 1.96 million tons of sculpture dioxide, 0.16 million tons of carbon monoxide and 0.39 million tons of nitric oxides. Similarly about 55 million tons of cow dung cakes burntinhomesemit 7.2 lakh tons of particulate matter, 5.4 lakh tons of hydrocarbons, 4.5 lakh tons of sculpture dioxide, 90,000 tons of nitric- oxides and 38,000 tons of carbon monoxide.