Mumbai Airport runway closure is starting to become a yearly thing now. They had shut both the runways for maintenance from October 18, 2016, through November 28, 2016. Then the main runway was shut for six days a week from February 2017 through April 2017. Then for six hours on October 23, 2018. Mumbai Airport also closed both the runways, three days a week, in February and March 2019.
Now, brace for impact for more delays and cancellations one more time. The main runway of Mumbai’s airport, 09/27, will be closed six days a week (Monday through Saturday) from November 7, 2019, through March 28, 2020. The closure will be from 09:30 AM through 05:30 PM (0400 UTC to 1200 UTC). Runway 09/27 will be available for operations on December 25, 2019, January 1 & 15, February 19 & 21, March 10 and 25, 2020.
During this period, the airport will work on re-carpeting the runway and repairs wherever needed. Unfortunately, due to 09/27 out of action for 8 hours, the operations will move to the secondary runway during this period, which takes a lesser number of planes as compared to the primary runway. Remember, Mumbai is the busiest single-runway operation globally and the second-busiest airport in India.
The consequence would be that you would see flights being delayed or cancelled a lot for these five months, and as a result, airfare would shoot up.
You are advised to look out for these changes in the coming days, if you are supposed to fly between 9:30 and 17:30 on a weekday to/from Mumbai Airport.