Officials in Chongqing in southwest China have been warned to strictly toe the Communist Party line following the announcement of an investigation into former party boss and Politburo member Sun Zhengcai. The official Chongqing Daily reported on Tuesday that the city had called a special meeting of senior cadres the previous day following Beijing’s decision to investigate Sun, once seen as a candidate for the next generation of Chinese leadership. High-flier in Chinese politics under investigation ahead of power reshuffle, sources say “It is the number one political requirement to defend the core status of General Secretary Xi Jinping,” said a statement released after the meeting. “[We] will proactively prevent and properly respond to possible sensitive events and negative impact[s],” it said. The meeting was led by Chen Miner, a close associate of Xi who replaced Sun as the party secretary for Chongqing this month. Sun is under investigation by the Central Commission for Discipline Inspection for “serious violations of party discipline”, a euphemism for corruption. He is the first incumbent member of the 25-strong Politburo placed under the party’s internal interrogation since Xi launched a sweeping anti-corruption campaign in 2012. The abrupt fall from grace of Sun came only a few months ahead of the party’s five-yearly top reshuffle in the autumn. The state-run tabloid the Global Times said in an editorial that the downfall of Sun could “result in some shock”. “But we firmly believe, through years of reforms, China’s political and social frameworks have become more stable than ever,” the editorial said. “[The shock] will not actually change anything.” Curse of Chongqing? Probe into Sun Zhengcai evokes memories of Bo Xilai’s dramatic fall Sun is the second party boss of Chongqingto fall from grace. One of his predecessors, Bo Xilai was imprisoned in 2013 in one of China’s biggest political scandals in decades, which also brought down the city’s former police chief, Wang Lijun. Sun and other Chongqing officials were chastised by the party’s disciplinary inspectors in February for failing to get rid of Bo and Wang’s influence. During the meeting in Monday, Chongqing officials reiterated the need to completely clean up the “pernicious legacy” of the pair, according to the Chongqing Daily .