The city soaked in sweat on Monday as high humidity pushed up the discomfort index 13 points above normal.

“It was unusually sultry today. The humidity was abnormally high,” said Gokul Chandra Debnath, the director of the Regional Meteorological Centre at Alipore.

The humidity ranged between 62 and 92 per cent. “In the afternoon, when the city suffered the most despite the temperature remaining near normal, the humidity was at least 14 per cent higher than what is usual for this time of the year,” said another official in the department.

Independent meteorologists said high humidity in the present conditions caused little or no rain as it only helped in cloud formation at lower levels of the atmosphere.

“Thundershowers or thunderstorms which bring relief from the swelter is triggered by cloud cover at a higher altitude. But the present conditions are not conducive to such cloud formation,” said O.P. Sharma, the chief meteorologist of a private agency.

According to the India Meteorological Department (IMD), the high humidity is because of abundant incursion of moisture under the influence of a low pressure trough in Bengal’s neighbourhood.

“Also adding to the moisture content is the strong flow of southwesterlies and south-southwesterlies, which bring moisture from the Bay of Bengal into south Bengal,” said an IMD official in Delhi.

The department, however, held out some hope for “isolated rain or thundershowers in Gangetic Bengal” over the next 24 hours.

The weather also affected power supply, with the demand in the CESC-served areas during peak hours crossing 1,600MW, resulting in a deficit of around 200MW. Areas under the state utility reeled under a shortfall of around 450MW.

Power cuts added up to two hours in the city and three hours in the rest of the state adding to the swelter agony.

“The weather condition pushed up the demand when there was a deficit in the state grid. The situation was better in the past few days as the weather was pleasant, keeping the demand under check during the peak hours,” said a CESC official.