They also followed that up with letters to the environmental bureau of the Qingyuan Economic Development Zone and other departments the following month.

Following the complaints, the environmental bureau visited two factories on Oct 21. On Oct 29, the bureau issued a notice to the battery firm asking it to comply with the rules before Nov 20.

The battery firm promised to rectify the matter on Nov 2.

Earlier, Guangzhou Daily had reported that the noise pollution and sewage monitoring reports - which was provided by the battery company - issued by the environment monitoring station of the city on Sept 3 showed they both met national standards.

The sulfuric acid mist and lead dust levels at the company also met the required standards, another report dated Nov 5 showed.