Everyone is talking about the Delhi smog. People are increasingly becoming concerned about its ill effect on health, work and quality of life.
As such, Delhi is one of the worst polluted cities in the world and conditions have worsened because of an add-on of several factors. Smog in Delhi around Diwali festivities is not happening for the first time and as things stand, it will not be the last either.
Smog increases hospital admissions and sick days. Major health effects of air pollution associated with are:
Respiratory: Short term decrease in breathing ability and increase in chest pains; inflammation of the lungs and damage to respiratory cells; permanent lung damage and reduced quality of life due to ozone; increased number of asthma attacks due to nitrogen dioxide.
Cardiovascular: There is a lack of oxygen in the bloodstream in people with heart disease, due to carbon monoxide.
Also, there is an increased risk of cancer and increased susceptibility to infection among children that aggravate asthma.
However, rather than being hysterical about the occurrence of smog as is being presented during television debates, one needs to understand causes and look for possible solutions.
After the withdrawal of monsoon, months of October and November bring in pleasant weather conditions, good for picnics and outdoor activities. Now, we are facing a situation where people are being advised not to go for a morning walk and children not to play outside.
There are multiple factors, which over a period have grown in intensity contributing to increase in the severity and frequency of smog over Delhi. It starts with burning of rice stubble by farmers in Punjab, Haryana and Western Uttar Pradesh in the month of October. With an increase in the cultivated area for paddy in recent decades, pollution caused by rice stubble burning has been increasing over a period.Evidence of this can be clearly seen in the satellite imageries.
The next culprit is dust pollution caused by large-scale construction activity going on in the NCR region including metro construction. Third in line is vehicular traffic, which has been increasing each year, contributing to higher pollution in NCR region.
Industrial pollution and garbage dumps are other contributing factors. During Diwali vehicular traffic increases substantially,with shopping and visiting relatives and friends resulting in traffic jams and higher pollution.
Firecrackers on Diwali day make the situation worse for a city already suffering from severe pollution.
Under normal conditions, nature has a diurnal, large-scale circulation features to disperse pollutants and mitigate the smog. However, on many occasions meteorological conditions like light wind, low temperatures, stable layer are such that rather than causing dispersion, these increase in the concentration of air pollutants resulting in smog persisting for days together.
It is not only Delhi alone which is suffering from smog. Many cities in United States and Europe have suffered from severe smog. The infamous Great London Smog of December 1952 resulted many premature deaths between December 5 and 10, 1952. However, this catastrophic event galvanized British Government to enact 1956 Clean Air Act, enforcement of which help in reducing the occurrence of smog in London.
India needs to holistically address the causes of smog, initiate necessary regulatory measures, and ensure their compliance. First is a ban on burning of rice stubble. It will require alternate solutions for the disposal of rice stubble. State governments have to enforce ban on crop burning with all sincerity to make it happen.
Next is control of dust pollution from construction sites. Each construction site should have dust-monitoring mechanism by local pollution boards with provision of heavy penalty on violation of permissible limits.
Since meteorological conditions can be very well forecast one week in advance, state government should take proactive measures such as shutting down of polluting industries, restricting interstate traffic and regulating city traffic so that smog like conditions do not develop.
SAFAR programme of Ministry of Earth Sciences provides air quality forecast for next three days, which could be used by State Government to close primary schools on days when severe air quality is forecast. All these measures require coordinated and sustained efforts by Central, neighboring states and Delhi government to address the causes of air pollution by regulatory and governance mechanism coupled with effective use of meteorological and air quality forecast to mitigate the impact of likely severe episodes of air quality such as smog.
Expert, Geography and You
AVM (Retd) Prof. Ajit Tyagi,
President, Indian Meteorological Society, Member, W.M.O. Monsoon Panel, Member, Working Group on Tropical Meteorology Research, Former Director General of Meteorology and Permanent Representative of India with W.M.O.