Even the Air Quality Index for Delhi on Thursday was recorded at 363, a dip from Wednesday's 398 - both fall in "very poor" category.
At least 20 flights were delayed, according to ANI. It started from east UP-Bihar on December 25, covered western parts, including Delhi, from December 31 and then to Punjab and further west by January 2. The sky will remain clear during the day, IMD said.
The Centre said it was monitoring the situation at the Indira Gandhi International Airport where flight operations were affected this week because of heavy fog, PTI reported. "Due to dense fog the visibility came down to 50m at Safdarjung at 8.30am, while it was less than 50m at Palam", said an official at India Meteorological Department.
A shallow fog would continue throughout the region all through the day, the Met said.
Almost 49 trains were delayed, and at least 12 cancelled due to dense fog and zero visibility.
"Chaired a meeting with all aviation stakeholders to review and refine the SOPs for fog-affected days".
Sinha also invited suggestions to improve the system performance.
Fog continued to wreak havoc for the third day in a row in the Indian capital, severely disrupting air and rail traffic Tuesday.
Delhi airport has advanced technology for low-visibility landings, called CAT IIIB.