A man holds a sign reading “Protest at PX Oil Refinery” during a rally in downtown Kunming, Yunnan Province against the planned construction of a CNPC petrochemical plant in the area on May 4. Photo: china.com

A child wearing a face mask participates in protests against the construction of an oil refinery in the nearby city of Anning, Yunnan Province on May 4. Nearly 3,000 Kunming residents participated in the protests. Photo: china.com

Residents of Kunming, the capital of Yunnan Province, wear masks and hold signs reading, "No PX in Kunming" in the city’s Nanping Square in protest against the proposed construction of a CNPC oil refinery in the area on May 4. Photo: china.com

Policemen watch as protestors in Kunming, the capital of Yunnan Province, rally against the planned construction of a China National Petroleum Corporation (CNPC) petrochemical plant on May 4. Nearly 3,000 Kunming residents gathered in the city’s Nanping Square to protest against the CNPC-proposed oil refinery. The protests were conducted without incident. Photo: china.com