Since the Met department declared the arrival of the southwest monsoon in the region last Friday, Gurugram, Delhi and other parts of the National Capital Region (NCR) have remained largely dry. Gurugram received scant rain on Monday and Tuesday and the India Meteorological Department’s (IMD) rain gauge recorded between 2mm and 4mm of rainfall both days. On the other days, the city received either no rainfall or only traces of precipitation. According to experts, the next four to five days are also likely to be dry.

According to the IMD, rainfall activity has become weaker over parts of NCR, Haryana and Rajasthan as the monsoon trough has continued to move north. “The monsoon trough has been north of Delhi-NCR and is currently moving further north. Because of this, heavy rainfall is expected in the foothills of the Himalayas, i.e. Uttarakhand, parts of Uttar Pradesh and Himachal Pradesh and regions south of the trough, like Delhi and Haryana, are likely to be dry,” said Kuldeep Srivastava, head, Regional Weather Forecasting Centre, New Delhi.

A monsoon trough is a belt of low pressure extending over a large area (from northwest Rajasthan till the Bay of Bengal), the position of which affects rainfall activity. When the trough shifts northwards, it leads to heavy rainfall in Uttarakhand, Himachal Pradesh and the northeastern states, and rainfall activity over the southern parts of the trough ceases.

“Currently in the NCR, as a result of the positioning of the monsoon trough, dry westerly winds are blowing, which are gaining heat from deserts in Pakistan and Rajasthan and leading to a significant decrease in rainfall,” said Mahesh Palawat, chief meteorologist, Skymet, a private weather prediction agency, adding that the region will be mostly dry till around July 15 when the trough shifts to the south of its current position.

Between July 1 and 9, Gurugram had a rainfall deficit of 55%.

Gurugram had received 82mm of rainfall on Thursday — a day before IMD declared the arrival of monsoon.

According to the IMD, light rain is expected around July 15, and predicted to intensify around July 18. However, experts said they don’t expect the rainfall deficit to be met. “July is likely to be a rain deficit month. While the rainfall around July 18 will be widespread and fill some gap, the activity is unlikely to remain the same throughout this month,” Palawat said.

Pollution levels up

Air quality in the city entered the ‘moderate’ category of the Central Pollution Control Board’s (CPCB) Air Quality Index (AQI) bulletin on Wednesday, after the year’s longest spate of favourable air from June 4 to June 9. On Wednesday, Gurugram recorded an average AQI of 138, up from 91 the previous day. The prominent pollutant, PM2.5, touched a maximum of 321ug/m3, more than five times the safe limit.  

Officials attributed this to a lack of rain in, and strong winds, which caused re-suspension of local dust particulates. According to the Early Air Quality Warning System for Delhi-NCR, wind speeds on Wednesday were at a maximum of 25kmph, and were mainly “strong surface winds”, responsible for kicking up dust and causing a mild haze

First Published: Jul 11, 2019 02:28 IST