Delhi recorded 33.5mm rain on Thursday-Friday, highest for December in 27 years

India Meteorological Department (IMD) data shows that on December 16, 2003, 28mm rainfall was recorded.

Delhi witnessed the highest rainfall recorded in a single day in the month of December in at least 27 years since 1991, from when data is readily available with the met department. From Thursday evening till Friday, Delhi recorded 33.5 mm rainfall.

Heavy rainfall hit the national capital on Thursday evening, and continued in several parts of the city through Friday. (Sonu Mehta/HT PHOTO)

Heavy rainfall hit the national capital on Thursday evening, and continued in several parts of the city through Friday. In Safdarjung, 33.5 mm rainfall was experienced while in Palam 40.2 mm and in Ayanagar 28.2 mm rainfall was recorded.

India Meteorological Department (IMD) data shows the highest rainfall ever recorded in the month was on December 3, 1923, when the city received 75.7mm rainfall. On December 16, 2003, 28mm rainfall was recorded.

The shower brought down the day’s temperature down by five degrees from normal. The maximum temperature on Friday was 18.27 degree Celisus, while the minimum temperature settled at 12.8 degree Celsius, four degrees above normal.

The rain and the increased wind speed helped improve air quality. According to Central Pollution Control Board (CPCB) data, from 429, in the ‘severe’ category, the air quality index (AQI) improved to 240 in the ‘poor’ zone.

On Tuesday and Wednesday, the wind speed hovered between 4-6kmph.

“This is the cumulative impact of rainfall, hailstorm and snowfall predicted in the western Himalayan region, for which a warning has been issued in those states,” said Kuldeep Srivastava, head of the IMD’s regional weather forecasting centre.

Another senior IMD scientist said the impact of rain will keep the air clean on Saturday.

“The AQI is likely to remain in the poor category or even go down to moderate. The minimum temperature is expected to reduce on Saturday,” the scientist said.

Explaining the reason behind last week’s spike in pollution levels, the scientist said the lowered temperature and shallow fog recorded in the early hours formed a blanket over the city and trapped pollutants closer to the ground. The low wind speed made matters worse as these pollution particles could not be blown away.

He said the pollution will return on Sunday, as there is a forecast of dense fog in the morning and the wind is also likely to slow down.

According to the central government-run System of Air Quality and Weather Forecasting and Research (Safar), the air quality may improve to ‘poor’ to ‘moderate’ on December 14.

“On December 15, the AQI may marginally deteriorate but will remain in the poor to lower end of the very poor category. Only a few biomass fire counts in northern India and with prevailing weather, zero biomass fire contribution in Delhi’s air,” the SAFAR forecast read.