GRAP, wind speed main causes for clean days: Experts
NEW DELHI: The emergency action plan GRAP and the increased wind speed are the major cause behind the better days this year and the experts predicted that the air quality will be much better than the last two years in Delhi this Diwali.
"Pollution is worse in winter because of adverse weather conditions, which lead to inversion (cold air settles); moisture (traps the pollutants) and poor wind (does not allow for dispersion). This is why even though the sources of pollution remain constant through the year, the level of pollution peaks in winter," said Anumita Roychowdhury of the Center for Science and Environment.
Officials at the Central Pollution Control Board (CPCB) said wind speed improved to 12kmph because a western disturbance passing through the northern plains and helped disperse pollutants trapped in the air.
Officials said traces of rain (0.2mm) recorded at the Safdarjung observatory, which is representative of Delhi's weather, helped clear the air. The levels of particulate matter — PM 2.5, PM 10 — primary pollutants in Delhi's air, which had shot up to four times the safe limit on Thursday, also improved on Saturday. The concentration of PM 2.5 is likely to increase sharply from November 5 owing to a change in wind direction and crop stubble burning.
The Graded Response Action Plan (GRAP) for the Poor to Very Poor air quality is already in force but the plan for Severe air quality will come only if the situation stays Severe for 48 hours," said Anumita Roy Chowdhury.
The Supreme Court-appointed Environment Pollution Control Authority (EPCA) has urged the Delhiites to use public transport for the first 10 days of November to keep a check on pollution. Noting that private vehicles contribute to 40 per cent pollution in Delhi-NCR, the EPCA urged people to reduce the use of private vehicles during this period and use public transport or other means.
On Tuesday, the air quality reached the 'severe' level, prompting authorities to adopt a slew of measures to combat pollution. Some of the measures include a halt on all construction activities involving excavation, suspension of civil construction, closure of stone crushers and hot-mix plants, among others. The Delhi Pollution Control Committee (DPCC) has also directed the Transport Department and the Traffic Police to intensify checking of polluting vehicles and control travel congestion in the region during November 1-10.