NEW DELHI: Temperatures topped 46 degrees C at several places on a torrid Tuesday, the season’s hottest day in Delhi, with the punishing prospect of a weeklong spell of broiling heat in store. The met department has sounded orange alerts for heatwave conditions across the city till May 25, reports Kushagra Dixit. The mercury crossed heatwave thresholds at multiple spots — Delhi Ridge logged a scorching 46.5 degrees C, Mungeshpur 46.1 and Ayanagar 45.5. Base station Safdarjung was at 45.1 degrees C, 4.7 notches above normal. This was the city’s first heatwave day in May in two years and the second this season. IMD warned that the region faces an unforgiving spell of blazing, dry weather in the next few days with little respite — unlike April and the first half of May, when western disturbances and dust storms brought relief. AQI deteriorated to ‘poor’, prompting the CAQM to impose Grap stage 1.While not restrictive, it imposes pre-emptive measures to curb pollution. The minimum was 28.2 degrees C at Safdarjung, two notches above normal, while Rajghat logged 31.2 degrees C, satisfying ‘warm night’ criterion of maximum temperature over 40 degrees and minimum at least 4.5 notches above normal.No May heatwave in 2025, six-day streak in 2024Heatwaves are usually followed by warm night conditions, which raises thermal distress of residents who get no respite from heat at any time of the day. For a heatwave to be declared, the maximum temperature should either be above 45 degrees Celsius, or above 40 degrees Celsius with departure above 4.5 degrees to normal. On Monday, Lodhi Road area logged a maximum temperature of 43.8 degrees Celsius, 4.8 notches above normal — which qualified for the heatwave. However, IMD officials said at least two consecutive days of high heat are needed for declaration of a heatwave.

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This makes Tuesday the first heatwave day of the month. In 2025, no heatwaves were recorded in May due to strong western disturbances and a cumulative rainfall of 185.92 mm. In sharp contrast, a streak of six heatwave days was logged in May 2024 — May 26 to 31 — with highest temperature reaching 46.8 degrees Celsius. IMD said the maximum temperature is expected to hover around 44-46 degrees Celsius on Wednesday and 43- 45 degrees Celsius from Thursday to Monday. The minimum temperature may spike to 29 degrees Celsius. Clamping Grap stage I across Delhi-NCR, CAQM stated: “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 strict enforcement of vigilance, mechanised sweeping etc. The air quality index on Monday was moderate at 173.