TIANJIN, China -- This coastal city has worked assiduously to foster loyalty to President Xi Jinping since the warehouse explosions that claimed some 170 lives here two years ago, a devastating incident that has given rise to conspiracy theories challenging the official investigation.

On a building under construction in the Binhai New Area coastal district outside Tianjin near the blast site, a red 100-meter-long banner is difficult to miss. It urges unity with the Communist Party with Xi as "core leader" to revive the great Chinese race.

Mayor Li Hongzhong, the local Communist Party secretary, has spearheaded the Xi-worshipping campaign. He has dotted the city with such slogans after taking over from Huang Xingguo, ousted last September on graft charges.

Li gave orders in February to bolster such efforts in preparation for the national party congress this autumn, plastering nearly 8,000 slogans on buildings, overpasses, billboards, train stations, bus terminals and other locations.

Holding that loyalty by definition must be absolute, Li has shown total devotion. As chief of Hubei Province, he rode the trains to understand people's daily lives after learning Xi had done so with a taxi. Li was already using the term "core leader" for Xi before the president was designated as such last October. When Sun Zhengcai lost his post as leader of Chongqing, Li quickly announced support for the party's decision.

The explosions of two years ago lie behind the campaign. The central government blamed mismanagement: Improperly stored nitrocellulose got too dry and ignited near highly explosive chemicals nearby. But unofficial theories still deem the incident a terrorist attack meant to intimidate Xi and other leaders. This is likely why Li wiped Tianjin clean of any signs of dissatisfaction with Xi and turned the city into one that pledges loyalty.

Forty-nine people were convicted of wrongdoing last November in connection with the blasts. The head of the logistics company that operated the storage facility received a suspended death sentence for such offenses as illegally storing hazardous materials. And this July, prosecutors indicted former Tianjin party secretary Huang on charges of corruption.

Construction is moving forward to turn the blast zone into a park, and apartments are rising in the surrounding area. After the incident, most residents moved away. But the new buildings are highly popular, and people are returning. The site has become an ideal venue for political posturing by Communist Party officials ahead of the leadership reshuffle at fall's congress as the explosions themselves fade into memory.