In the year 1996, the Supreme Court took a radical decision to protect the Taj Mahal by ordering the closure of numerous iron foundries, ferro-alloys industries, rubber processing, lime processing, engineering, chemical industries, brick kilns and refractory units situated in and around Agra, lying in an irregular zone of 50 kilometers width that was named as the Taj Trapezium Zone (TTZ).

This decision was taken by the apex court in response to a writ petition filed by environmentalist and lawyer MC Mehta, who claimed that pollution around the Taj Mahal was affecting the beauty of the monument of love and its pristine white marble was becoming yellow. The court also instructed a restricted zone of 500 meters to be created around the Taj Mahal, banning all petrol and diesel vehicular traffic, besides ordering 24 hour power supply for Agra city to protect the monument from generator fumes.

However, after almost 20 years, the level of pollutants in the air around the Taj Mahal hasn't shown any remarkable improvement. The air pollution records from the past decade show that the pollution hasn't dropped by an appreciable margin and has in fact increased in some aspects, spurring the Central Pollution Control Board (CPCB) to establish a permanent weather monitoring station inside the Taj Mahal.

According to a summary data provided by the CPCB since 2002, the level of SO2 and NO2 have been hovering around 5 and 20 ppm respectively, while Respirable Suspended Particulate Matter (RSPM) and Suspended Particulate Matter (SPM) levels have been fluctuating wildly, always staying on the high side.

Talking to India Today, Agra Tourist Welfare Chamber President Prahalad Agarwal said that the principal reason for high RSPM and SPM levels around the Taj Mahal was the dry Yamuna riverbed. The river runs dry for most of the summer months and due to high winds, the sand gets carried away towards the Taj Mahal, where it acts as an abrasive on the soft marble, corroding it. He said that the ill-fated Heritage Corridor scheme is also partially responsible for the SPM and RSPM pollution in the area because of the accumulation of loose sand on this reclaimed riverbank.

He said that the SO2 and NO2 pollution levels are basically due to a large number of automobiles in Agra that run on diesel and petrol. Besides vehicles, the irregular power schedule in Agra also promotes the use of diesel-based standby power generators even a few meters away from the outer wall of the Taj Mahal.

Environmentalist Rajiv Gupta said that the closure of 292 iron foundries and other pollution causing factories in Agra was a welcome step by the Supreme Court, but this has not brought a tremendous change in pollution levels, as was hoped, mainly because there is no restriction on pollution causing vehicles in Agra after the restricted zone of 500 meters around Taj.

Gupta further added that pollution control check was not mandatory in Agra and almost 90 per cent of the vehicles in the city were running without a no-pollution certificate. He said that even the district administration of the city had not made any arrangements for the vehicle owners to get their vehicular pollution checked and as a result, vehicles as old as twenty years and more were running without any restriction in Agra, causing pollution that was in fact affecting the Taj Mahal and the health of the people of this town now.