New Delhi, June 13 -- The sun showed no mercy on Thursday, but it was the air-heavy, wet, and unmoving-that brought Delhi to a near standstill. For the fourth straight day, isolated parts of the city slipped into heatwave conditions, with Safdarjung, the Capital's base station, recording a maximum of 43.9degC - four degrees above normal and the highest so far this year. While the temperature eclipsed Tuesday's 43.8degC, it was the suffocating humidity that turned the day unbearable. According to the India Meteorological Department (IMD), Delhi recorded a maximum of 42.2degC at 2.30pm, but with 39% relative humidity, the Heat Index (HI) touched 53.6degC. By 5.30pm, it soared to 54.4degC - the most punishing so far this season. Delhi's highes...