The announcement on Wednesday that Beijing's Deputy Party Secretary Lu Xiwen is under investigation for suspected violations of Party discipline came just a day after the disclosure that Shanghai's Vice-Mayor Ai Baojun is under scrutiny.

There had been speculation about why no high-ranking officials of Beijing or Shanghai municipalities were being investigated. But the announcements about Ai and Lu send a clear message that no official is exempt from the anti-graft campaign, unless he or she is clean.

In fact, more than 70 ministerial or vice-ministerial level officials have either been investigated or indicted for abuse of power since the anti-corruption campaign was launched in 2012. There is now no province, autonomous region or municipality directly under the auspices of the central government where a ministerial-level official has not been either indicted for corruption over the past three years or is under investigation.