Supreme Court has been monitoring enforcement of its orders, but a lot more needs to be done 

1973 | Proposal to set up a refinery at Mathura, 40 km from the Taj Mahal sparks debate over the danger it would pose to the Taj

1974 | Expert panel headed by S Varadarajan submits report saying emissions from refinery would be limited to one tonne/hour

1978 | Joint Parliamentary Committee headed by Karan Singh opposes Mathura refinery

1981 | Government closes 2 thermal power stations in Agra and replaces coal with diesel as the fuel in railway shunting yard

1981-82 | Central Pollution Control Board (CPCB) demarcates TajTrapezium Zone (TTZ)

1982-83 | Mathura refinery commissioned. In two years SO2 levels around the Taj Mahal spiral (it was noted at 859 kg/ hr in 1993)

1983 | Taj Mahal bags World Heritage Site tag. Centre declares Agra- Mathura region as air pollution protected area; prohibits setting up of polluting industries

September 3, 1984 | SC issues notice on petition by M C Mehta, saying pollution from units in Agra and the adjacent town of Firozabad, and Mathura refinery is a threat

January, 1993 | SC orders National Environmental Engineering Research Institute (NEERI) and UPPCB to help industries set up air pollution control devices

January, 1993 | SC orders Uttar Pradesh Pollution Control Board (UPPCB) to identify polluting industries in Agra; notices served to 511 units

July, 1993 | NEERI says units using coal and coke as fuel are the major polluters; suggests changes in TTZ boundaries

August 27, 1993 | Closure order passed against 212 industries that failed to install air pollution control devices

October 1993 | NEERI submits report on SO2 emission control measures for Mathura refinery, recommends use of natural gas as fuel

February 25, 1994 | SC examines NEERI recommendations on use of gas fuel in Mathura refinery and other units in TTZ (Mathura refinery's switchover to gas fuel completed in 2005)

March 31, 1994 | Uttar Pradesh asked to submit list of units in TTZ for relocation.

August 8, 1994 | Court informed that gas pipeline for Mathura refinery would be completed by December 1996. (At present, 90-odd units run on gas and electricity in TTZ)

April 29, 1994 | Considering 57,800 workers would be affected, SC orders setting up another panel to probe pollution sources; panel constituted under S Varadarajan

April 1995 | Varadarajan panel submits report, recommends relocation of industries out of TTZ

August 3, 1995 | SC orders the Centre and Uttar Pradesh government to prepare relocation scheme

1996 | World Monuments Fund publishes list of 100 most endangered sites, which includes the Taj

1996 | SC orders uninterrupted power to Agra; to expedite work on Gokul Barrage (completed in 2001) and Agra Barrage (yet to be constructed). Decides to monitor implementation of its orders

February 20, 1996 | SC takes note that none of NEERI's recommendations had been enforced by the Centre

March 3, 1996 | SC orders expediting construction of bypass road to check pollution from 14,000 trucks passing through the city (road functional at present)

May 10, 1996 | All brick kilns ordered to stop operating within 20 km from the Taj (no bricks kilns operate in the area now)

December 30, 1996 | 292 units in Agra asked to shift to natural gas or apply for plots outside TTZ. Non-complying industries directed to be closed from April 30, 1997

March 24, 1998 | Polluting vehicles prohibited within 500 metre of the Taj Mahal

September 4, 1998 | Court takes note of NEERI and CPCB report on sewerage system for Agra; no pumping station allowed within 500m of the Taj

November 11, 1998 | SC asks Union environment ministry to release funds for green belt

December 12, 1998 | All commercial activity in protected monuments in TTZ banned (no shop operates within the Taj premises at present)

February 23, 1999 | Cabinet Committee on Economic Affairs approves schemes worth Rs 222.21 crore for projects to improve air, water and land in Agra 

May 17, 1999 | TTZ Pollution (Prevention and Control) Authority constituted to monitor schemes for protecting the Taj

November 29, 2000 | Uttar Pradesh sanctions Rs 4.56 crore for Agra Heritage Fund

November 7, 2000 | SC directs setting up four air quality monitoring stations in Agra. These become functional in 2002 at the Taj Mahal, Etmatud- daula, Rambagh and Nunhai

November 3, 2000 | SC directs CPCB to lay down special air and noise pollution standards for TTZ. (Ecologically sensitive area standards are applicable in TTZ since 2009)

December 14, 2000 | SC orders the Centre to release funds to ensure survival of 1,215,500 saplings planted by the Uttar Pradesh forest department for a green belt around the Taj at a cost of Rs 4.03 crore

October 3, 2001 | Foundry owners asked to file undertaking to switch to gas-based technology by October 10, 2001, failing which they would close (187 close shop)

April 11, 2002 | SC takes note of CPCB report, saying air quality has still not improved. UPPCB asked to ascertain reasons

July 16, 2003 | SC orders CBI inquiry into Rs 175 crore Taj Heritage Corridor scam after diversion of the Yamuna river, to reclaim over 30 ha between Agra Fort and Taj Mahal for food plazas and shops, is noticed

August 19, 2003 | SC orders crackdown on illegal mining in Mathura as it was said to be contributing to pollution

December 2013 | NEERI prepares comprehensive environment management plan; says use of coal and biomass by units, and growth in vehicle numbers, behind the pollution

June 2013 | Agra Development Authority orders petha units to switch to gas fuel or relocate away from the Taj. The process is going on

January 2015 | All commercial vehicles operating around Taj ordered to shift to CNG by July 31 following an Indo- US study on the discolouration of the Taj

March, 2015 | SC pulls up Uttar Pradesh for making false claims about planting trees to compensate for trees felled for development projects 

November 2015 | Supreme Court ordered that the crematorium near the monument be shut down

October 2017 | Observing that a parking lot near Taj could be an environmental hazard, the SC ordered to demolish it

December 2017 | While observing the ad hoc measures are not enough, the apex court directed the UP government to prepare a comprehensive vision document to protect the 17th centure mausoleum.

June 2018 | Union minister for culture and environment implemented the 'Taj MahalDeclaration to Beat Plastic Pollution' and made residents staying in 500-metre radius of the monument pledge to reduce use and litter of single-use plastic.

Source: Supreme Court judgements and media reports