A senior Chinese official whose remarks last year about disgraced former security tsar Zhou Yongkang propelled him to fame, said yesterday there was "no point" in speculating which "big tiger" would fall next. "In the anti-corruption campaign … there is no upper limit and there is no [untouchable official]," Chinese People's Political Consultative Conference plenum spokesman Lu Xinhua told a Beijing press conference ahead of today's opening of the annual plenary meeting. President Xi Jinping's ongoing anti-graft drive, worsening pollution and economic uncertainty are expected to be the focus of the major political event, during which the national legislature - the National People's Congress - will also start its full meeting on Thursday, with Premier Li Keqiang presenting his annual work report at a joint session of both bodies. Lu, formerly the foreign ministry's top official in Hong Kong and also last year's plenum spokesman, spoke of the public and authorities' shared determination to wipe out graft. But he declined to speculate if more top cadres would be netted. "But it is perfectly understandable that the public and media organisations believe that if bigger tigers do exist, they should be exposed," he said. Shortly after Lu spoke, the PLA Daily announced that more than a dozen senior officers - including Guo Zhenggang , son of retired Central Military Commission vice-chairman Guo Boxiong - had been snared in the military's graft crackdown. Last year, four state-level incumbent or retired officials - including Zhou and CPPCC vice-chairmen Ling Jihua and Su Rong - came under formal corruption investigations. Asked to comment on Zhou's fate during the CPPCC plenum at the time, Lu gave the South China Morning Post a standard party line, adding subtly: "That's all I can say. You know what I mean." Yesterday, Lu told the media that the graft cases involving senior CPPCC members mostly had nothing to do with their roles in the political advisory body, but that they had "greatly hurt the CPPCC's reputation". "The CPPCC will not be a sanctuary for corrupt officials." Lu also reiterated Beijing's stance regarding electoral reform for selecting Hong Kong's next chief executive in 2017. The decision must be based on the Basic Law and the national legislature's resolutions on the matter, and be in line with Hong Kong's current situation, he said. Asked if some Hong Kong lawmakers' calls for restarting the entire 2017 political reform process from scratch would affect Beijing's view on the matter, Lu said the central government's position was consistent and clear - Beijing supported the Hong Kong Special Administrative Region in its bid to attain universal suffrage in an orderly manner and in accordance to law. On pollution, Lu said: "Last time, President Xi said the 'Apec blue' could not be maintained, but we hope that it can be repeated for the Olympics, and we are really looking forward to it." He was referring Beijing's bid to host the 2022 Winter Games.