Spice Jet Airlines — delay of flight for more than one hour

Address:

Mumbai City, Maharashtra

My flight from mumbai to kolkata sg-490 on 29 november 2019 which had a schedule departure at 0035 is now delayed by more than one hour (Reason-congestion in air traffic) does traffic congestion only hampers spice jet flight or this is just an excuse
I had an onwards journey from kolkata but now i will miss my flight because of this delay
Who will take the responsibility??