Mumbai, Nov. 14 -- The city witnessed a further dip in morning temperatures on Friday, with the minimum temperature at the Santacruz observatory falling to 18.9degC, 2.9degC below normal and lower than the 19.6degC recorded on Thursday. Officials at the India Meteorological Department (IMD) attributed the fall in temperature to cold northerly and north-easterly winds blowing from the anticyclonic circulation over north-west India. At the Colaba observatory, however, the minimum temperature remained high, at 23.8degC, which was normal but lower than Thursday's 25degC. Both south Mumbai and the suburbs recorded above-normal maximum temperatures: 35degC in Colaba and 35.3degC in Santacruz. Meanwhile, after five days of a spike during Diwali, Mumbai's overall air quality index (AQI) dropped significantly to 109 on Thursday, into the moderate category, with PM10 as the primary pollutant. Between November 8 and November 12, the AQI had ranged from 132 to 172....