The northern Indian plains have again come into focus as one of the world’s most-polluted regions. What makes the Hindi Belt’s air so foul?

Rapid economic development and a soaring population have driven up pollution levels in the past decade. The northern plains also have among the highest population densities in the world.This translates to higher pollution from human activities. We all are aware of the number of factors contributing to the hazardous level of air pollution in the Indo-Gangetic plains like vehicular emission, dust and wildfires, large-scale construction, industrial pollution, power plants, garbage dumps, crop burning, electronic waste and so on.

As per the WHO reports, almost all of the most polluted cities in India are located in the north of Uttar Pradesh, Punjab and Rajasthan dominating the list. While there is a sharp decline in air quality in most cities of north India, southern India, on the other hand, is enjoying satisfactory air quality.

So why North India chokes on bad air? A major reason for high pollution in the Indo-Gangetic plains is its geography. Located next to the Himalayas, this is a wind convergence zone which transports pollution from other places into these regions.The plain is landlocked, with the Himalayas largely blocking air pollution from escaping to the north. In addition to local sources of pollution, Indo-Gangetic cities also get pollution from neighboring regions and other parts of India. Seasons bring their own influence. In spring, dust blows in from the Thar Desert, adding large natural particles to the mix. During summer, winds sweep towards the Indo-Gangetic plains through south India and from the north through the Himalayas, converging in the plains. The convergence factor shows up the most in winters when the region sees spells of dense fog due to cold winds coming from the west and northeast. Poor people begin to burn wood and trash to stay warm, further fueling the haze. Fog traps pollutants, leading to sharp deterioration in air quality. The boundary layer which separates the ground atmosphere from the upper atmosphere comes much closer to the ground because of the cooler temperatures. That makes it much harder for pollution to disperse.

Southern India, on the other hand, enjoys a spell of good air partly driven by settling of pollutants due to northeast monsoon showers. Moisture from the south enters the north and traps pollutants near the surfaced. In Delhi, fine particle pollution rates are ten times higher than that of Chennai, which has ten times more vehicle density but is coastally located, without the surrounding industrial areas. (Ref.1) Kerala, which is both on the coast and has little industrial activity, with an economy dominated by service activities such as tourism and remittances, has many of the least polluted cities in the country.

North India has fertile alluvial soil which also contributes to pollution. Alluvial soil is highly dusty when dry. The Indus-Ganga belt is the world’s largest stretch of uninterrupted alluvium deposits. As fertile as alluvium is, it is composed of loose unconsolidated particles. Thus, dry alluvial soil significantly contributes to wind-blown dust.

A desert area will always have higher particulate matter since the air composition includes varying sizes of dust particles. The worst-polluted cities in the world as named by the WHO, almost never include a coastal city but are ones in desert regions. Many European cities too faced a challenge from pollution the past winter. London and Paris both reported particulate levels above permissible levels and had to put in place emergency measures. Many air pollution source apportionment studies tell us that pollution is a trans-boundary concern and travels across man-made boundaries. The problem of air pollution, thus, has to be addressed both locally and globally.

“The NDA government’s pro-activeness to extend LPG connections among the rural poor and households below the poverty line is another welcome move.” Anumita Roychowdhury, the head of the air pollution and clean transportation programme at CSE, said. Pradhan Mantri Ujjwala Yojana scheme has provided 37 million women living below the poverty line with LPG connections. Such schemes will also help cut the indoor air pollution that plagues much of rural India, which is not covered in the WHO analysis.

Assuring all technical and policy support, Centre has also emphasized in the implementation of National Clean Air Programme. The drafts aim at improving the air quality monitoring in India and propose to increase the number of pollution monitoring stations. Currently, the System of Air Quality and Weather Forecasting and Research (SAFAR) serves as the apex forecaster of pollution trends in Delhi, Mumbai, Pune, and Ahmedabad. India is tying up with the United States and Finland to develop a pollution-forecast system which will help in anticipating particulate matter (PM) levels at least two days in advance and at a greater resolution than what is possible now. Also, its key focus would be to develop forecasts around the “stubble-burning season” that adds to the pollution woes in the winter.

Natural causes combined with man-made causes make the plains the pollution hotspot of the world. Even the best science and technology will not succeed in reducing emissions and improving air quality if it is not considered in a broader framework of the economic development of the country, raising awareness of public health risks and a change in attitudes and regulation towards poor quality fuels.

Writer Ankita Singh is Content Developer in Civil Services Institute and currently living in New Delhi.


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