The Met department termed the Delhi storm as "cumulonimbus" and attributed it to western disturbance over Pakistan. NCR areas of east Delhi, Noida and Ghaziabad were most affected by the storm. Thousands of people were stranded outside Metro stations and on roads as traffic almost came to a halt due the storm and high-speed dusty winds blowing at a speed of over 90 kmph.

The dust storm which struck at 4:58 pm caused technical snag in the over-head power network of the Noida City Centre- Dwarka metro line affecting metro services in other lines too.

Met office said similar weather conditions are likely to persist for over the next two days. At least 12 flights were diverted due to the storm, an IGI official said.

The city saw massive traffic jams as the storm uprooted trees snapping power lines in many areas and affecting traffic lights leading to chaos on the streets.

"The cumulonimbus brings tall thunderstorms and dusty winds with a speed of over 92 kmph and are caused because of western disturbance, which is currently over Pakistan.

"The meeting of cold air and hot air on the Indo-Gangetic plains causes low pressure area and also lot of instability. This results in severe thunderstorm," IMD Director General L S Rathore said. The storm affected northeast Haryana and the NCR. But parts of east Delhi, Noida and Ghaziabad were affected the most, he said.

Pic: Delhi at 5 pm and 6 pm