Facebook declined to comment, following past practice when asked about WhatsApp’s difficulties in China.
Lokman Tsui, an internet communications specialist at the Chinese University of Hong Kong, said that WhatsApp seemed to have been severely disrupted starting on Sunday. But he said that some WhatsApp users might still be able to use the service.
The Chinese authorities have a history of mostly, but not entirely, blocking internet services, as well as slowing them down so much that they become useless. The censorship has prompted many in China to switch to communications methods that function smoothly and quickly but that are easily monitored by the Chinese authorities, like the WeChat app of the Chinese internet company Tencent, which is based in Shenzhen.
“If you’re only allowed to drive one mile per hour, you’re not going to drive on that road, even if it’s not technically blocked,” Mr. Tsui said.
The disruption of WhatsApp comes as Beijing prepares for the Communist Party’s congress, which starts Oct. 18. Held once every five years, the congress chooses the party’s leadership, which in turn runs the country. Next month’s meeting is expected to reconfirm President Xi Jinping’s nearly absolute grip on power, but considerable uncertainty remains over who will join him on the Standing Committee of the Politburo, the party’s highest-ranking group.
Over the past several years, China has not only stepped up censorship but also closed numerous churches and jailed large numbers of human rights activists, lawyers and advocates for ethnic minorities.
The shutdown of WhatsApp prompted considerable dismay on Chinese social media.
“Losing contact with my clients, forced back to the age of telephone and email for work now,” one user complained on Weibo, a Twitter-like microblogging site.
“Even WhatsApp is blocked now? I’m going to be out of business soon,” another Chinese social media user said on Weibo.
In China, even the use of email is fading as residents embrace the convenience of WeChat. The messaging service, which has 963 million active users, bears some similarities to WhatsApp but has a wider array of features and one crucial difference: close ties to the government. This month, WeChat sent a notice to users reminding them that it complied with official requests for information.
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