LONDON — The death of a British man and three other climbers on Mount Everest highlight concerns about congestion on the world's tallest mountain as a high number of hikers make their way to the top in the current climbing season.

Robin Haynes Fisher, 44, died at 8,600 meters above sea level on his descent from the Himalayan summit after feeling ill, Meera Acharya, director of Nepal's department of tourism, told the Himalayan Times on Saturday.

His is one of several recent deaths that comes amid concerns that a traffic jam of mountaineers is making the ascent and descent even more treacherous during this summer's brief window to reach the world's highest peak.

Three Indian nationals died Thursday while trying to climb Everest, which sits on the border of Nepal and Tibet, an autonomous region of southwest China, officials and mountaineering agencies confirmed to NBC News on Friday.

Nihal Bagwan, 27, died after collapsing from exhaustion on the balcony area of the mountain where he was waiting in a line to reach the summit, according to Krishma Poudel of Peak Promotion, a mountaineering agency in Nepal.

Anjali Kulkarni, 54, and Kalpana Das, 49, also died while descending the mountain Thursday, according to Mira Acharya, the director of Nepal’s Department of Tourism. The cause of their deaths is not yet known, she added.

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The news comes after it was confirmed that an American man from Utah died earlier this week after having reached the summit and fulfilling his life’s dream, his children told NBC affiliate KSL-TV. Don Cash, 55, was a passionate climber who had left his job to join the Seven Summits Club — whose members attempt to summit the highest mountain on every continent.

Tweeting a picture of a long line of climbers waiting to get to the summit Wednesday, the British broadcaster and adventurer Ben Fogle, the U.N. patron of the wilderness, called on the countries that share Everest to limit the number of climbers on the mountain, suggesting instead for a marathon-style lottery system for climbing permits.

As of May 19, the Nepalese Tourism Department said it had provided 381 permits to climb Everest.

Since Edmund Hillary and Tenzing Norgay became the first people to reach the summit of the mountain in 1953, attempting the 29,029-ft peak has become more and more popular. Expeditions can cost tens of thousands of dollars, according to the British Mountaineering Council. A total of 560 people reached the summit of Everest last year, according to Acharya.

Poudel explained the mountain was busy during peak season. “There’s a long queue during the summertime as there’s a limited window to climb — a lot of people tried to summit yesterday and day before," she said, using a British word for line.

Poudel said that lines to reach the summit started from the balcony area of the mountain but said she did not know how long Bagwan had been waiting there. “Before you reach the summit, you have to wait and every minute counts at the height,” she explained, but cautioned that she could not say if waiting there had caused Bagwan’s death.

“You’ve been walking since 8 a.m. the day before without eating or a proper rest and exposed to that temperature, there’s a high risk of being frostbitten and hypothermia,” she added.

Poudel said that Bagwan was barely conscious when Sherpas brought him down to Camp 4 — the last pit stop ahead of what is commonly referred to as the “death zone” before the summit. He died there at around 11:30 Thursday night, she added.

She would not comment on whether officials should limit the number of climbers on the mountain but acknowledged that if there were fewer people, it would reduce the risk that they suffer from exhaustion in the line. “Waiting for hours at that kind of height really takes a toll,” she said.

Acharya, of the Department of Tourism, said she could not comment on the question of whether the lines were dangerous for climbers.

Saphora Smith reported from London and Phil McCausland from New York.