Eleven people have died on Mount Everest this year, as the world’s highest peaks are swarmed by climbers. This is the deadliest season on Everest since 2015.

Nepal government officials say a string of bad weather has made summiting Mount Everest difficult this season, though Everest regulars suggest that overcrowding and inexperienced climbers may be to blame.

“There were more people on Everest than there should be,” Kul Bahadur Gurung with the Nepal Mountaineering Association said in an interview Associated Press.

Most of the deaths have been attributed to altitude sickness. It’s not unusual for climbers and sherpas to experience altitude sickness leading to death, or to suffer from dangers like exposure or avalanches.

A record breaking 381 permits were granted to climbers to summit the world’s highest mountain this year, but the number of bodies on the mountain is even higher as climbers often rely on sherpas to guide them and help carry luggage and gear.

Because so many people have been climbing the mountain, there have also been a record number of ascents this season. 825 people successfully summited Mount Everest so far. This number includes climbers from the Chinese side of the mountain, as China has begun issuing climbing permits as well to drive tourism and revenue for the country.

While the Nepalese government has given out a record number of permits this year, the Chinese government has been more restrictive in granting permits.

Mount Everest is a huge source of revenue for Nepal which is one of the world’s poorest countries. According to Mohan Krishna Sapkota, secretary at the Ministry of Tourism and Civil Aviation, Nepal makes roughly $300 million each year from Everest related activities, as each permit costs $11,000.

There is no indication that Nepal will restrict climbing permits, but the government did say inexperienced climbers may cause problems on the mountain.

Perhaps it’s the record number of permits being given out to anyone with the money and the doctor’s note assuring good health, but other concerned parties believe expedition companies that bring inexperienced climbers to the highest mountain in the world are partly to blame for the Everest tragedies.

“The easy headline is, ‘Overcrowding is killing people on Everest,’ ” Alan Arnette, an expert on Everest, said in an interview with USA Today. “But the root cause of that line in the photo is low-cost guide companies bringing in a new demographic of climbers who don’t belong there. Limiting the number of permits isn’t the solution. People should have to have climbed an 8,000-meter peak, and they need to tighten up who can guide there because right now they let anybody guide.”