On Wednesday night, the capital experienced its worst fog since 2003, which seemed unlikely to lift in a hurry.

“This is one of the worst fog conditions since 2003,” said BP Yadav, Director, India Meteorological Department.

“Unless there are strong northerly winds to blow it away, the fog is here to stay,” added a Met department official.

By 10 pm, visibility was almost zero. “It is bad not only in Delhi, but also in many parts of northern India,” said Yadav.

More than 20 trains were cancelled and another 32 in Delhi were rescheduled.