NGT panel appointed after air pollution complaint finds glaring lapses at ACC cement plant in Himachal Pradesh

The committee also reported that at least seven complaints had been lodged against the cement plant by local residents over the last three years.

The committee, also comprising scientist Dr Narender Sharma from the Central Pollution Control Board, and HPPCB Regional Officer Pawan Sharma, visited the cement plant on January 18. It was formed following a complaint lodged in September 2024 by Kashmir Thakur, a resident of Khetad village near Barmana who alleged severe air pollution caused by the plant’s operations.

The tribunal was informed that the cement plant had been shut down for annual maintenance from January 3 to February 8, 2025. When the committee visited the plant on January 18, only one kiln was operating, that too at 40 per cent capacity. Acknowledging the need for a more thorough investigation under full-capacity operations, the committee requested an additional eight weeks to submit its final report.

In its report, the committee stated, “The plant was directed to implement measures to control accidental discharge of pollutants, especially dust emissions during grid failures. However, the plant had yet to implement these measures. Dust emissions were observed in areas around the clinker, ash, and cement silos, causing distress to nearby residents.

“The consent to operate mandated the plant to establish a three-layer tree plantation along its boundary to mitigate air and noise pollution, but this critical step remained unfulfilled. Furthermore, while the plant had installed a truck tyre washing system at the raw material exit, there was no mechanism to remove oil and grease from the recycled wastewater. Additionally, the plant was still in the process of installing a tyre-washing system at the cement exit point to prevent dust from being carried outside the premises.”

In December 2024, the tribunal directed the committee to review the status of its earlier judgment—issued in December 2015—wherein an environmental compensation of Rs 50 lakh had been imposed on the ACC cement plant. The committee stated that it was in the process of examining documents submitted by the plant regarding this issue.

In his complaint, Kashmir Thakur alleged that ACC Limited has been manufacturing cement for several years, but the plant’s dust separation system was either improperly functioning or inadequately installed. As a result, flying dust generated during cement production has been accumulating on pathways, roads, and residential areas, significantly affecting nearby residents. He further said the plant has failed to effectively manage and control fugitive (unintentional) emissions.

Complainant suspicious

When contacted, Thakur raised doubts as to how the plant could be shut for maintenance days before the inspection of the joint committee. He said, “We believe that authorities are merely buying time. We want the inspection of the cement plant by independent experts. We will raise our demand during the next date of hearing on February 25.”

Cement manufacturing at the ACC Limited plant involves grinding and blending raw materials containing calcium oxide (such as limestone) with a siliceous material (such as clay, shale, and sand) along with certain additive or corrective materials (such as alumina and iron ore) and then burning the mixture at high temperatures in a kiln.

The resulting ‘clinker’ is cooled and then ground with gypsum to produce the finished product, ordinary portland cement, or with pozzolanic material like fly ash to produce blended cement. The major raw materials used in the manufacture of cement are limestone, gypsum, and fly ash, while coal is used as fuel in the kilns.

The major raw materials used in the manufacture of cement are limestone, gypsum, fly ash, and coal, which is used as fuel in the kilns. The limestone for the existing plant is obtained from a captive limestone mine located about 4.0 km (by road) from the cement plant. The crushed limestone from the mine is transported through a land-enclosed belt conveyor to the cement plant. The raw material is processed in a cement kiln to make the clinker. The kiln is fitted with a suspension preheater system to reuse the heat from the flue gases.

The unit operates on a dry process and also uses waste heat from the cement kilns to dry the raw material. The remaining waste heat, if any, is used to generate power by deploying a waste heat recovery system. Gypsum and fly ash are ground in the cement mill in required proportions to produce cement. The cement thus produced is stored in silos and sent to the packing plant, where it is packed through packing machines and dispatched.