new delhi, April 25 -- Indian airlines' international flights plunged to a four-year low in March, as Iran's retaliatory strikes across the Gulf following US and Israeli attacks disrupted key aviation routes, triggering airspace closures and flight cancellations. International departures by Indian airlines fell 40% on-year to 11,284 flights in March from 18,502 a year earlier, as per data from the Directorate General of Civil Aviation (DGCA). Overseas passenger traffic dropped more than 36% to 1.84 million passengers, compared with 2.9 million in March last year. Routes to West Asia account for almost half of the international capacity of Indian carriers. Since the conflict began, more than 10,000 flights have been cancelled through April. Daily departures to West Asia have plunged to about 80-90 flights from 300-350 earlier, a senior civil aviation ministry official said. The affected destinations include Dubai, Sharjah, Doha, Riyadh and Dammam. Air India Express was the worst-hit among local carriers. The low-cost carrier of the Air India Group, which has a heavy exposure to the region, saw departures plunging 68% to 1,263 in March from 3,928 a year ago. Passenger traffic sank 66% to 169,000 from 496,000, underscoring the airline's reliance on Gulf routes. It is not clear if the carrier, which connects 17 overseas destinations including Dubai, Doha, Abu Dhabi and Sharjah, is redeploying under-utilized aircraft on other routes. International departures at IndiGo, India's largest airline, fell 36% to 5,238 flights in March from 8,231 a year earlier. Passenger traffic shrank 37% to 809,000 from 1.28 million. It has cut flight frequencies on the West and Central Asian routes following operational constraints including airspace closures. However, "the European network that includes Manchester, Amsterdam, London and Athens remains unchanged, although flying times are now longer", a senior IndiGo executive said, requesting not to be named. "Numbers clearly reflect the West Asia crises playing out for Indian airlines. Dubai has restricted foreign airlines to one daily flight. Same restrictions or curbs have not been levied by India on carriers based out of Dubai. And this has a pronounced impact on players like Air India Express," said captain Mohan Ranganathan, an aviation expert. "Air India Express is also the hardest hit since over 50% of its international routes cover the Gulf." Queries emailed to the civil aviation ministry and Indian airlines remained unanswered till press time. This marks the lowest level of international operations since overseas air travel from India resumed on 27 March 2022 after covid. The outbreak of war in Iran on 28 February led to widespread airspace closures and operational disruptions across one of the busiest aviation corridors globally. Airlines are also facing supply-side curbs and rising costs. Restricted access to West Asia's airspace and a continuing ban on using Pakistani airspace have forced carriers to take longer, more circuitous routes to destinations in Europe and North America. Jet fuel prices have almost doubled since March, further squeezing margins. The disruption has kept international airfares elevated and constrained capacity on key routes. Fuel surcharges have also gone up for international routes....