Heavy rain accompanied by gusty winds washed away pollutants in the city, taking the Air Quality Index to the "moderate" category. However, along with the relief came problems as several areas reported water-logging that left commuters stranded for hours.
Delhi witnessed its cleanest day of the year on Tuesday, as rains accompanied by strong winds lashed the city causing the overall Air Quality Index (AQI) to reach 'moderate' levels against the usual 'very poor' or 'severe'.
"Monday night's rain along with sufficient wind speed was enough to wash away air pollutants. More than the rain, it is faster winds which cleaned up Delhi air significantly," the System of Air Quality and Weather Forecasting and Research (SAFAR) website said.
The agency said that although the impact of rain will last for some time, AQI is predicted to remain in the 'moderate' to 'poor' range for the next three days.
Earlier, the national capital saw 'moderate' air quality days in November and December, for a day each, a Central Pollution Control Board official told IANS.
The overall air quality of Delhi at 4 p.m. on Tuesday was recorded at 104 (moderate), a drastic improvement from Sunday's 'severe' air quality of 404. In the national capital, Faridabad at 87, Greater Noida at 95, Gurugram at 98 and Noida at 95 fared much better than Delhi in the 'satisfactory' category. Ghaziabad, however, was recorded in the same category as Delhi with its AQI at 104.
As per the India Meteorological Department (IMD), this sudden change in the weather is due to two western disturbances over the northern hills and its induced cyclonic circulation over the northwestern plains which are expected to remain till the end of the week.
The IMD said that due to clouds covering the northern plains, the maximum and minimum temperature would drop and increase by three and four degrees Celsius, respectively.
"On Wednesday, the maximum temperature is expected to further drop to 19 degrees Celsius, against Monday's 22.6 degrees Celsius, while the minimum is likely to hover around 10 degrees Celsius," an IMD official said.
According to the Met, during the next 48 hours, rains might fade away from Delhi. "There might not be rain on Wednesday, however, some drizzle is expected on Thursday," the weather body said. From Friday onward, rain is unlikely to occur again and moderate to dense fog might envelop the national capital.
On Thursday, across 35 areas in Delhi, where pollution is actively monitored, the average concentration of PM 2.5 and PM 10 was 51 and 74 micrograms per cubic meter, respectively.
The concentration of PM 2.5 and PM 10 across 48 monitoring stations in the NCR stood at 50 and 72 microgrammes per cubic meter, respectively.
