On November 22, 2025, the International Association of Ultrarunners (IAU) announced the postponement of the 2025 IAU 50k World Championships, originally scheduled for December 7, in New Delhi, India. Although a new date hasn’t been set, the IAU has stated that it will announce one within the next week.
The women’s podium from the 2023 IAU 50k World Championships held in Hyderabad, India. Photo courtesy of the International Association of Ultrarunners.
In a press release, the IAU said that the decision was made after discussions with the Athletics Federation of India and the local organizing committee. The cancellation, just two weeks before the event, is likely the result of worsening air quality in the city. In recent days, India’s Supreme Court, supported by the Commission for Air Quality Management in the area, has also requested that all schools cancel outdoor activities for the next one to two months.
Poor air quality in the area is common in November and December, with historical fine particulate air quality numbers spiking to nearly 300 parts per million (ppm) annually since 2015. Winter-time inversions lead to the buildup of pollutants around the New Delhi area, which has a population of over 30 million people. Several factors combine to increase the number of pollutants in the air, including farmers burning their fields in preparation for the spring.
In the days leading up to the cancellation announcement, the Air Quality Index in New Delhi was 370 ppm, which is well within the range considered severe. The IAU said, “While we recognize the significant effort and preparation invested by athletes, coaches, and federations, the health and safety of all participants must remain our highest priority.”
National teams will be allowed to change their teams until December 21.
[Editor’s Note: We’ll update this article when a new date for the event is set.]
