Delhi reeled under its hottest day of the season on Tuesday as temperatures crossed 46 degrees Celsius in several parts of the city, pushing residents into severe heat stress and forcing authorities to activate emergency pollution control measures. The India Meteorological Department (IMD) has issued orange alerts for heatwave conditions till May 25, warning that the coming days may bring little relief from the scorching weather.The capital’s base weather station at Safdarjung recorded a maximum temperature of 45.1°C, nearly five degrees above normal. Ridge station emerged as the hottest spot at 46.5°C, while Mungeshpur touched 46.1°C and Ayanagar recorded 45.5°C. The temperature spike marked Delhi’s first officially recognised heatwave day in May in two years.Delhi Temperature: Get ready for long spell of dry and punishing heatWeather officials said the city is likely to remain trapped in extremely hot and dry conditions for at least the next six days. Unlike April and early May, when western disturbances and dust storms brought intermittent relief, the current weather pattern offers no such comfort.IMD has forecast maximum temperatures between 44°C and 46°C on Wednesday and around 43°C to 45°C till Monday. Minimum temperatures are also expected to remain unusually high, possibly touching 29°C in some areas.The last time Delhi saw temperatures touch the 46°C mark was on May 29, 2024.Dry winds from Pakistan and Thar desert worsening conditionsPrivate weather forecaster Skymet Weather linked the rising temperatures to hot and dry winds sweeping across north and central India.“Pre monsoon activities will remain absent from NW and Central India for at least a week. Dry & hot winds blowing across Pakistan and Thar desert will further increase the temperature over Punjab, Haryana, Delhi, Rajasthan, UP, MP & Maharashtra,” said Mahesh Palawat, vice president, Skymet Weather.Delhi night temperature also highThe heat has not eased even after sunset. Rajghat recorded a minimum temperature of 31.2°C, meeting the criteria for a “warm night”, a condition where nights remain excessively hot after an extreme daytime temperature.Officials say warm nights significantly increase thermal discomfort because people do not get enough cooling time during the night. The minimum temperature at Safdarjung settled at 28.2°C, two degrees above normal.For the IMD to declare a heatwave, the maximum temperature must either cross 45°C or remain above 40°C while staying at least 4.5 degrees above normal for two consecutive days.A sharp contrast from May 2025This May has turned dramatically different from last year’s weather pattern. In 2025, Delhi did not record any heatwave day during May due to repeated western disturbances and heavy rainfall measuring 185.92 mm.In comparison, Delhi witnessed a six-day heatwave spell between May 26 and May 31 in 2024, when temperatures climbed as high as 46.8°C.Delhi pollution rises along with the heatThe soaring temperatures also pushed Delhi’s air quality into the “poor” category. The city’s Air Quality Index (AQI) touched 208 on Tuesday afternoon, the highest level recorded since April 28, according to Central Pollution Control Board data.Following the spike, the Commission for Air Quality Management (CAQM) enforced Stage 1 measures under the Graded Response Action Plan (GRAP) across Delhi-NCR.“AQI has shown increasing trend and was recorded at 208 (‘poor’) on Tuesday… The sub-committee, accordingly, has decided to invoke all actions under stage I of the extant Grap in the entire national capital region, with immediate effect.”The measures include stricter monitoring, mechanised road sweeping and intensified anti-pollution enforcement drives.On Monday, Delhi’s AQI stood at 173, which falls under the “moderate” category.