The first dense fog of the season hit the capital early Monday morning, and, as feared, threw the region out of gear. As visibility dropped to less than 50m at places, flights were delayed and even cancelled, train services remained paralyzed and at least one life was lost in a road accident.

At the airport, a much bigger disruption was averted when the instrument landing system on the main runway was rectified just in time. The new runway came under dense fog for about three hours during which time only the main runway was in use.

About 200 flights were delayed on Monday, some up to five hours, and at least nine cancelled aslow visibility procedures were in place for almost 12 hours.

Rail services, already reeling under the impact of heavy fog between east UP and Bengal, were further disrupted as the fog cover moved west into the capital. As many as 40 trains were cancelled and 100 others suffered delays.

The fog cleared up for a very short duration in the afternoon but was back in the early evening hours. Visibility at IGI Airport had fallen to 500m by 7pm.