Overnight rain spell gives Delhi its wettest Jan in 22 years
A widespread spell of rain on Friday night gave Delhi its wettest January in 22 years, just eight days into the new year, showed data from the India Meteorological Department (IMD), as the showers mopped up the city’s pollution, giving the Capital an air quality index (AQI) lower than 100 for the first time since mid-October.
The IMD’s Safdarjung observatory, considered to be the official marker of the city’s weather, recorded 41mm of rain on Saturday. The last time Delhi saw more rain in January was in 1999, when the city recorded 46mm of precipitation on January 7.
The Palam weather station received 47.6mm rain during the same period, which according to IMD, is the highest rainfall in 27 years. On January 9, 1995, the Palam station recorded 52.2mm of rainfall.
Weather officials attributed the rain to a western disturbance and the induced cyclonic circulation. The western disturbance is over north Pakistan and neighbouring areas, while the induced cyclonic circulation is over east Rajasthan and neighbouring areas, the IMD said in a press release on Saturday.
RK Jenamani, senior scientist, IMD, said while the western disturbance is a routine phenomenon, the widespread rain this time is due to a “strong” western disturbance.
“Some western disturbances are so strong that their tail lies till the central part of the Arabian Sea. The weather activity that we witnessed was on account of a huge western disturbance that picked up moisture from a vast area of the central Arabian Sea and covered areas such as Punjab, Haryana, Rajasthan, Madhya Pradesh, Delhi, Himachal Pradesh and Uttarakhand,” said Jenamani.
He said Punjab, Haryana, and parts of Rajasthan also recorded high rainfall. “The western disturbance resulted in high rainfall in a number of areas. That doesn’t happen normally. The western disturbance was very active this time,” he said.
The rain resulted in temperatures dropping in the national capital; on Saturday, the maximum temperature at the Safdarjung station was 16.4 degrees Celsius (°C), three degrees below normal and nearly four lower than Friday’s reading of 20.3°C. The minimum temperature on Saturday was 15.2 degrees Celsius, with the difference between the maximum and minimum temperatures on Saturday being just 1.2 degrees.
“An interesting thing to note is that the difference between the day and night temperature is only one degree. That is very unique,” said Jenamani.
The IMD said fairly widespread rainfall is likely to continue in Delhi on Saturday and decrease thereafter. As per the IMD’s weekly forecast, a cloudy sky with light rain is expected on Sunday.
The air quality in the city also improved on Saturday, thanks to the rain. Delhi recorded an air quality index (AQI) reading of 91 (satisfactory), an improvement from Friday’s AQI of 182, as per the Central Pollution Control Board’s (CPCB) 4pm bulletin.
The CPCB classifies an AQI of zero to 50 as “good”, 51-100 as “satisfactory”, 101-200 as “moderate”, 201-300 as “poor”, 301-400 as “very poor” and above 400 as “severe”.
The Union ministry of earth science’s air quality monitoring centre, System of Air Quality and Weather Forecasting and Research (Safar) attributed the improvement in AQI to strong dispersion of pollutants and wet deposition of particulate matter on account of rain. “From 9th (Sunday) onwards air quality is likely to degrade due to gradual decrease in maximum and minimum temperatures as well as wind speed, all contributing to low dispersion of pollutants,” the forecast said.
In the aftermath of rain, waterlogging was reported from various parts of the capital. Areas such as New Friends Colony, Dabri, Bindapur, Tilak Nagar, and Chattarpur were inundated, traffic officials said.