At least 175 IndiGo flights were cancelled early on Thursday in India as chaos at key airports worsened, after stringent government regulations on crew safety norms disrupted roster planning at the country’s largest airline.

The disruptions have left thousands of travellers stranded for three days now.

IndiGo, which has a domestic market share of more than 60 percent, on Wednesday cancelled at least 150 flights across major cities.

On Thursday, 73 flights were cancelled at Bengaluru airport, its spokesperson said. Around 30 were cancelled in Delhi, and 68 in Hyderabad, according to airport sources.

The airline did not respond to a request for comment on Thursday, but has said this week that the cancellations were due to various factors, including stricter flight duty-time limits introduced by India’s aviation regulator to tackle pilot fatigue.