How tall is tallest peak? Historical row over Mt Everest height explained

The revised height of Mt Everest puts an end to the decades-long dispute between Nepal and China. All you need to know about the controversy

"This is a historic day. The new height of Mt Everest is 8,848.86 metres," Nepal and China announced on Tuesday after they remeasured Mt Everest at 8,848.86 metres, over six decades after India conducted the previous measurement in 1954.

The revised height of Mount Everest puts an end to the decades-long dispute between the two neighbours on the height of the world's tallest mountain that straddles their shared border. Describing Mount Everest "an important symbol of the China-Nepal traditional friendship," Xi Jinping said it is agreed by both countries as the boundary peak and the "Peak of China-Nepal Friendship," the Xinhua report said.

Mount Everest height controversy explained

The exact height of Mount Everest had been contested ever since a group of British surveyors in India declared the height of Peak XV to be 8,778 metres in 1847.

The revised height of Mt Everest puts an end to the decades-long dispute between the two neighbours on the height of the world's tallest mountain that straddles their shared border.

The peak of Mt Everest or as the Chinese call it 'Mt Qomolangma' played a significant role in the settlement of the boundary between Nepal and China, after Beijing gave up its claims over the whole mountain as part of its territory after it took control of Tibet in 1950.

The dispute was finally settled in 1961 after the intervention of the ruling Communist Party of China founder Mao Zedong, who suggested that the boundary line should pass through the summit of the Mt Everest, which was agreed by Nepal.

When was Mount Everest last measured

The 2015 earthquake triggered a debate among scientists on whether it had affected the height of the mountain.

The government subsequently declared that it would measure the mountain on its own, instead of continuing to follow the Survey of India findings of 1954.

New Zealand, which shares a bond with Nepal over the mountain, provided technical assistance in May 2019. Sir Edmund Hillary, the first climber on the peak along with Nepal’s Tenzing Norgay in May 1953, worked as the mountain’s undeclared brand ambassador to the world. China’s measurements were done separately.

Method used to measure Mount Everest

Damodar Dhakal, Joint Secretary and spokesperson for Nepal’s Department of Survey, said: “We have used the previous methods applied in ascertaining the height as well as the latest data as well Global Navigational Satellite System (GNSS). The fact that both Chinese and Nepali data tallied shows the accuracy.”

When was Mount Everest measured earlier

Estimation by British surveyors: A group of British surveyors in India declared the height of Peak XV, as it was initially called, to be 8,778 metres in 1847.

Measurement by Survey of India, 1954: Mount Everest was measured for the second time by the Survey of India in 1954 from Bihar, using instruments like theodolites and chains, with GPS still decades away. The elevation of 8,848 m came to be accepted in all references worldwide — except by China.

A Chinese survey in 1975 obtained the figure of 29,029.24 feet (8,848.11 metres), and an Italian survey, using satellite surveying techniques, obtained a value of 29,108 feet (8,872 metres) in 1987, but questions arose about the methods used.

In 1999, a US team put the elevation at 29,035 feet (nearly 8,850 m). This survey was sponsored by the National Geographic Society, US. Once again, the rest of the world accepted the elevation of 8,848 m, barring China.