The head of the World Health Organisation said on Thursday that investigations into the origins of the COVID-19 pandemic in China were being hampered by the lack of raw data on the first days of spread there and urged it to be more transparent. A WHO-led team spent four weeks in and around the central city of Wuhan with Chinese researchers and said in a joint report in March that the virus had probably been transmitted from bats to humans through another animal. “We ask China to be transparent and open and to cooperate,” WHO Director-General Tedros Adhanom Ghebreyesus told a news conference on Thursday.