The Centre for Research on Energy and Clean Air says Russia has become China’s biggest supplier of oil as the country sold discounted crude to Beijing amid sanctions over the Ukraine war.
The Center said imports of Russian oil rose by 55% from a year earlier to a record level in May, displacing Saudi Arabia as China’s biggest provider.
China has ramped up purchases of Russian oil despite demand dampened by Covid curbs and a slowing economy.
The Center said Russia earned almost $100bn in revenue from fossil fuel exports in the first 100 days of the country’s invasion of Ukraine, despite a fall in exports in May.
In February, China and Russia declared their friendship had “no limits”.