The mercury in Delhi dipped two degrees below normal to 7°C on Tuesday compared to 12.4°C (three degrees above normal) a day earlier while the air quality remained in the moderate category and moderate fog enveloped the city and dipped the visibility to 200 metres at Palam and 500 metres at Safdarjung.

Strong surface winds of 25-30 km per hour were expected in the city on Wednesday and the minimum temperatures between 7 to 9°C were expected until the weekend. The maximum temperatures were likely to hover around 20°C. On Monday, the mercury went up to 21°C, or two degrees below normal.

An India Metrological Department official said cold northwesterly winds have led to the drop in the mercury. “Skies too are beginning to clear out, following the withdrawal of an active western disturbance.”

Reduction in fog and a gradual rise in temperatures over the last few days prompted the Delhi education department to order the resumption of normal school timings from Tuesday. Schools were earlier directed against starting before 9am or functioning beyond 5pm.

Delhi’s average air quality index (AQI) was 147 (moderate) at 9am on Tuesday. It was 180 (moderate) a day earlier. The improvement has been attributed to good wind speed and rain over the last two days, which helped disperse pollutants or bring them down.