Tata Chemicals made this disclosure to stock exchanges on Tuesday. The company said that it has written to the CPCB to rescind the order after an independent lab confirmed that its samples comply with prescribed norms.

The Haldia unit, with a capacity of 1.2 million tonnes per annum, manufactures chemicals like sulphuric acid and phosphoric acid, and crop nutrients such as NPK complexes, diammonium phosphate (DAP) and single super phosphate. The Tata Chemicals website said that it is the only company to have a manufacturing unit for DAP and NPK complexes in West Bengal. The company told the CPCB that the report by the independent lab was also approved by the West Bengal Pollution Control Board and the ministry of environment and forests.

The Haldia plant, however, has been shut since last month for annual repair and maintenance work as well as for relocating the ammonia pipeline. Ammonia is a feedstock for manufacturing NPK complexes. The plant was expected to reopen on April 16. The company received CPCB's shutdown notice on March 11.