The failure of the country's two biggest oil producers to meet key environment targets in 2012 has once again put them in the spotlight.

It has also sparked fresh discussions over what kind of social responsibilities our powerful State-owned enterprises should undertake in their painstaking pursuit of bigger market shares.

According to the Ministry of Environmental Protection, China National Petroleum Corporation, the parent of Hong Kong-listed PetroChina, failed to meet its chemical oxygen demand reduction target last year, and China Petrochemical Corporation, or Sinopec, failed to cut nitrogen oxide emissions as required.