Beijing ranked as the top science city globally, followed by New York, Boston, San Francisco/San Jose and Shanghai, in the Nature Index global science city 2020 rankings released during the recently concluded Zhongguancun Forum.

Four other Chinese cities — Nanjing, Wuhan, Guangzhou and Hefei — ranked among the top 20 global science cities.

David Swinbanks, founder of the Nature Index, said a concentration of talent, funding, research institutions and other resources is crucial for the top five global science cities to maintain their leading positions.

He spoke via video at the forum, saying that cooperation between the top five cities is pretty close.

A key metric used by the index is "share" — a city's contribution to science publication with its own country. Beijing's contribution to China was 21 percent, more than double that of any other city in the top five — New York (10.3 percent), Boston (9.5 percent), San Francisco/San Jose (8.4 percent) and Shanghai (10.9 percent), according to STM Publishing News which focuses on science, technical and medical publishing professionals of the world.

Beijing is also home to the Chinese Academy of Sciences, which, at the institutional level, leads the index in share and acts as a central hub of Chinese scientific collaboration.