For the month of December 2022, fog disruptions were the biggest cause of schedule disruption accounting for about 81 % of flight cancellations, showed DGCA data.

from Times of India https://timesofindia.indiatimes.com/business/india-business/airlines-flew-47-more-pax-in-2022-vs-2021-but-number-still-below-pre-covid/articleshow/97128990.cms