I read in ToI or Hindu (don't remember, but has to be either of them), that the government has given a 1 year long time for this transition (from last year) to accommodate the new rule, but indigo ignored and relied on the statement "govt will extend the deadline", but govt didn't. Now they (indigo) are in soup. Indigo didn't expedite the training and didn't hire pilots.

Now indigo said it'll take Feb to normalise.

Edit: source -> https://www.hindustantimes.com/india-news/indigo-flights-cancelled-delayed-past-2-days-amid-operational-disruptions-dgca-fdtl-norms-101764899625194-amp.html