Darkness fell prematurely over the Capital on Friday afternoon as gloomy clouds lashed the city with a heavy downpour, taking unprepared commuters by surprise and sending the mercury down even before it had begun its seasonal rise. Drowning the sun in layers of grey and black, the sudden pall of murkiness warranted use of headlights by vehicles all over the city as early as 4 p.m. while the steady torrent of rain caught most commuters off guard. Cars and two-wheelers at most places were forced to crawl while pedestrians scurried about looking for cover. Power load falls The welcome April showers that reminded many of the monsoon months of July and August sent the minimum temperature reeling down to a pleasant 17.5 degrees Celsius while the maximum temperature recorded was 30.5 degrees. Friday was also the coolest April 4 in the past five years, with the previous maximum and minimum temperatures ranging from 31/19 degrees in 2007, 36/18 degrees in 2006, 35/18 in 2005, 36/21 in 2004 and 36/24 in 2003. Providing a welcome break from the extended dry spell, the rainfall, pegged at 18.6 mm by the Meteorological Department, also eased things for the beleaguered Power Department. Delhi Trancso Limited Director (Operations) S. R. Sethi said the sudden spell of rain had decreased the load by around 500 MW. While the maximum load on the system had been 3,000 MW on April 4 last year, this time it was just 2,628 MW, the official added. Flights affected The imperious weather, said to be the consequence of a low-pressure area prevailing over Rajasthan, also affected flights at Indira Gandhi International Airport here with Air Traffic Control sources saying several flights had been delayed on account of the stormy conditions. While one Jetlite flights was diverted to Lucknow, several others seeking to land in Delhi were held up in air due to the protocol of using just one runway during thunderstorms. Even the metro railway service paused momentarily to contemplate its state of readiness to deal with the torrential onslaught.