MUMBAI: Mumbai’s airport, India’s second-busiest after Delhi , needs urgent attention as it is reaching the saturation point at a time when air traffic in the country is growing at the quickest pace in the world, aviation industry executives and experts said.With record rains that pounded the city this year, it has been particularly harrowing for airlines with frequent shutdowns of the airport causing huge delays. Just about 60% of flights could take off or land on time in August — in fact, airlines have recorded a steady fall in monthly on-time performance at the airport since the beginning of the financial year in April. The Directorate General of Civil Aviation has yet to release the numbers for September, the month that recorded the strongest spates of rain and thundershowers throwing flight schedules at the airport awry.In the past one month, the airport has also seen an aircraft getting stuck on the side of the runway. Pilots and airline executives complain also about potholes in the taxiway.“It’s a nightmare to fly in and out of Mumbai now,” said a senior executive at a full-service Indian carrier. “And it’s getting worse every single day. Now it has come to a situation wherein you can operate a flight remotely on time only during absolutely perfect weather. Otherwise, not a chance.”Mumbai is also the world’s busiest airport with single-runway operations — it has two runways, but they intersect each other and so only one can be used at a time. Mumbai handled 839 flights on a daily average in 2016, overtaking London's single-runway Gatwick airport that handled 767 flights. During peak hours, Mumbai handles one landing or take off every 65 seconds. In a note released on Friday, Sydney-based consultant CAPA-Centre for Aviation highlighted Mumbai under airports with the highest risk of saturation — it could reach the point as early as this year or next.The airport has spent Rs 10,000 crore in upgrading its terminal but is the only major airport not to have significantly invested in the development of its runway. “Available terminal capacity is around 60 million, but the airport will saturate at 50-52 million due to airside limitations,” the CAPA note said.