New Delhi, June 10 -- A squally dust storm, with speeds hitting 120kmph at Palam, swept through Delhi-NCR on Tuesday evening, disrupting flight operations at the Indira Gandhi International (IGI) Airport and evening traffic movement at some locations. This was the fastest wind to hit Palam since April 27, 2005, when the speed touched 138kmph, according to data shared by the India Meteorological Department (IMD). At least two flights were diverted to nearby airports, with over 400 flights delayed as per the flight-tracking portal FlightRadar24, as of 9pm. "The highest wind speed of 120kmph was reported over Palam, followed 80kmph at Pusa and 64kmph at Safdarjung. A squall was reported over both Palam and Safdarjung," said India Meteorological Department (IMD) scientist Krishna Mishra. The IMD classifies it as a "squall" when the wind speed increases by at least 16 knots (30kmph) to a minimum of 22 knots (41kmph) while lasting for at least one minute. Experts termed the storm a typical "pre-monsoon" activity, caused by a combination of high heat through the day and adequate moisture in the air through a cyclonic circulation, leading to convention and the formation of thundery clouds within a short window. The IMD has forecasted similar weather on Wednesday, with high temperatures during the day and the possibility of thundery development in the evening. An orange alert for rain is in place for Thursday, as a western disturbance approaches. Delhi's maximum temperature was 43.5 degrees Celsius (degC) on Tuesday, four degrees above normal and the highest so far this month. However, high humidity meant the "real feel" or heat index (HI) hovered around 45degC during the day. The weather changed rapidly after 5.30pm, with the skies turning overcast and gusty winds and squall between 6.30pm and 7.30pm, with patchy drizzle recorded in the city too. Mahesh Palawat, vice President at Skymet Weather, said there was high surface heating during the day, with a trough and cyclonic circulation towards Pakistan, gradually feeding moisture. "This led to the formation of thunder clouds."...