Diwali hangover: Gurgaon air least polluted in NCR, 56% lower than last year

GURGAON: Thanks to Supreme Court's ban on sale of fire-crackers, Gurgaon reported its cleanest Diwali in the last four years. The city also remained the least polluted in the Delhi/NCR region.

The peak PM2.5 level recorded on Friday was 324.9 micrograms per cubic metre (g/m³) — an increase of nearly 134% over Thursday evening's peak of 138.56. However, it is about 53% lower than last year's peak, which was 690.98 g/m³ the day after Diwali. In 2015, 2014 and 2013, PM2.5 level hovered at 397 g/m³, 315 g/m³ and 221 g/m³, respectively. As per national standards, PM2.5 level should not exceed 60 g/m³.

At 397, the Air Quality Index (AQI) remained 'Very Poor' on Friday — the highest in the past three months. However, once again, it was the lowest among NCR cities. While Delhi reported an AQI of 403 (severe), Ghaziabad was the worst in the NCR, with AQI of 412 (severe). Noida also reported 'severe' AQI of 402.

Experts, however, preached caution, pointing at the concentration of particulate matter, which is continuously going up in Gurgaon, and could yet lead to an emergency. "This year, air quality was definitely better on Diwali than last year. However, if you look at PM2.5 level in Gurgaon, it's rising continuously, because of low wind speed which is not assisting the dispersion of particulate matter in the atmosphere. Stubble burning and diesel generator sets are other big contributors to rise in air pollution. We're worried this could soon lead to an emergency situation," said Niranjan Raje, former member of Environment Pollution Control Authority (EPCA) and a Gurgaon resident. He added the authorities should have taken steps in September itself, but failed to do so.

As a result, authorities are gearing up to implement the Graded Response Action Plan (GRAP). HSPCB regional officer Jai Bhagwan told TOI, "If the situation continues to remain poor over the next 36-48 hours, we will take all required measures as per GRAP. The problem is, wind speed is very low, which might aggravate the situation. However, PM2.5 level was lower than last year, thanks to Supreme Court's ban on sale of fire-crackers, followed by intensive awareness drive carried out by HSPCB."

If PM2.5 level continues to be above 300 g/m³ (considered 'emergency' level), authorities might order a temporary shutdown of construction activities, highly polluting factories and the entry of trucks into Gurgaon. If required, odd-even scheme for private vehicles could also be introduced.

Centre for Science and Environment (CSE) has predicted the situation could persist over the next 48 hours. Shambhavi Shukla, research associate of CSE's clean air programme, told TOI, "As meteorological conditions are likely to continue, we predict PM2.5 levels to remain the same in Gurgaon for the next 48 hours. As per norms, GRAP can be implemented if PM2.5 level remains over the 'severe' level continuously for 48 hours. However, we can't wait for an emergency situation to arise. Authorities should roll out a combination of long-term and short-term strategies, that include strictly following construction norms, better public transport systems, etc., to deal with the situation in the long run."