Thunderstorm, accompanied with light rain, occurred in Delhi this morning, bringing down the temperature. However, it caused inconvenience to officer-goers as traffic was heavy on many roads in the city. The thunderstorm was preceded by a dust storm that dimmed visibility. The wind speed was 12 knots. Safdarjung weather station recorded 2.2 mm of rainfall, said a MeT department officer. According to MeT department forecast, the day will be overcast with light rain expected later on.