How did IndiGo fly into severe turbulence?

IndiGo, India's largest carrier, faces one of its most severe disruptions, as hundreds of flights have been cancelled since Tuesday. It blamed crew shortages, new duty-time rules, technical breakdowns, and congestion. But why has IndiGo been hit the hardest? Mint explains:

- BY ABHISHEK LAW

What are the new duty time limitations?

India's latest Flight Duty Time Limitations (FDTL) is designed to reduce pilot fatigue and improve safety. IndiGo, which runs one of the largest networks in Asia with over 2,300 flights a day, struggled to rebuild rosters in time. The new norms require overhauls to duty schedules. The earlier weekly rest period for pilots was 36 hours. This has increased to 48 hours. Night duty is from 0000 hours to 0600 hours, an extension by one hour. Also, the number of landings during night operations is now two, instead of six. No more than two consecutive night duties are allowed. This means, airlines will need more pilots.

Why do pilot fatigue, FDTL norms matter?