Air quality set to worsen in north India
May turn hazardous within weeks as a result of Diwali fireworks, crop stubble-burning and calmer weather.
Delhi’s air has been exceptionally clean in recent weeks because of the extended monsoon and strong wind, but these conditions will soon reverse, according to the air quality monitoring unit of the National Institute of Tropical Meteorology, which is under the ministry of earth sciences.
“High winds speed that persisted for the last two days is likely to slow down by today evening. Deterioration of air quality towards the middle of the moderate category is predicted for tomorrow (Wednesday),” it said in its latest assessment.
Drying up of northern India will further deteriorate Delhi’s air, it said. The withdrawal of the monsoon, expected this week after a month’s delay, is another threat to northern India’s air quality because of the formation of anticyclonic conditions in the atmosphere, which are associated with clear skies and very calm wind conditions.
“Both will lead to stagnant weather conditions (for instance, low wind speeds, descending air, and compressed boundary layer), which favour rapid fine particulate matter formation and accumulation of pollutants. The situation becomes worse if it is encountered with any additional internal (such as firecrackers) or external (such as stubbleburning) emission source,” said the forecast. “In a landlocked city like Delhi, it may lead to rapid accumulation and may trigger extended extreme pollution events.”
The late withdrawal of monsoon is also expected to generate more farm fires in northern India which generate dense, toxic fumes. The ripening of the summer-sown crops has been delayed because the monsoon lingered on in northern India for more than a month after its usual withdrawal time.
This has reduced the time available for farmers to prepare the ground to plant the next crop.
While officials say that the states had launched an awareness drive to discourage farmers from burning harvest residue, a few farmers have already started lighting fires, and others are likely to follow as they have only a two-week window to prepare their fields.
Last year, some officials in Chandigarh said that farmers of northern India should not be blamed for pollution in Delhi and said the capital’s air was toxic because of its own local emissions. These officials said air quality in many parts of northern India was relatively clean when farmers were burning harvest residue.