New Delhi, Dec. 11 -- The government is examining how IndiGo's international operations remained relatively unaffected even as its domestic network collapsed in the first week of December as the airline failed to keep up with new crew rostering rules aimed at reducing pilot fatigue and improving safety, officials aware of the matter said. Between December 1 and 9, IndiGo cancelled 4,290 domestic flights, while it scrapped only 64 international flights, showed data submitted by the airline to the government, which HT has reviewed. On December 4, two days after the scale of the problem became apparent, IndiGo cancelled 611 domestic flights but only 14 international services. At the peak of the disruptions on December 5, the airline cancelled 1,588 domestic flights, about 79% of its domestic schedule. The same day, only 35 international flights --11% of the overseas schedule -- were cancelled, the data showed. IndiGo, on average, was scheduled to operate around 2,000 domestic flights and 300 international flights daily between December 1 and 9, according to the data. "We are investigating to check how the airline managed to have the least impact on their international flights when their entire system was severely disrupted," one of the officials said. IndiGo, the country's largest airline, is facing increasing scrutiny over the ongoing disruptions that left thousands of passengers stranded at airports across the country. The examination of the domestic-international imbalance in cancellations assume significance as pilots and analysts have claimed that the airline deliberately allowed the chaos to play out hoping that this would force the civil aviation ministry to relax the new norms that were fully implemented from November 1. The civil aviation regulator did relax some of the Flight Duty Time Limitation (FDTL) rules, including those on night flights by pilots, on December 5 but the cancellations and delays continued over the weekend. Data presented in Parliament showed how far the airline had stretched its self-touted lean operations structure -- IndiGo's pilot strength saw a 7% reduction between March and December even as the airline was scheduled to fly 6% more flights in the winter season compared to the summer schedule. Officials said the government is examining whether route planning, crew deployment, rostering choices or commercial considerations contributed to the imbalance. "The consistency of international operations during a period of widespread domestic disruption is an important aspect of the review," a senior official said. After passengers reported long delays, last-minute cancellations and limited communication across airports in the past week, the government issued a show-cause notice to the airline, and on Tuesday, curtailed 10% of the airline's flights scheduled for the winter season. IndiGo is yet to give a detailed explanation to the show-case notice. But in an initial response, the airline said the cancellations were caused by a "compounding effect of multiple factors", including crew unavailability, minor technical glitches, etc....