Cause of concern
Air quality around the Taj is much better now than it was 15 years ago. But respirable suspended particulate matter (RSPM) is still two times the permissible limit
technology and environment to visit the Taj Mahal on April 10.The committee pointed to black spots on the minarets flanking the mausoleum,and asked the Archaeological Survey of India (asi) to seek expert advice,if required,to clean the marble facing.“We are concerned by news reports that the directions of the Supreme Court for preserving the Taj Mahal have not been complied with and the discolouration of the monument is a reality,”says Ashwani Kumar,Rajya Sabha member and chairperson of the committee. Members of Parliament who visited the Taj are expected to submit a report to Parliament during the current budget session.
But all this leaves crucial questions unanswered. Why is the Taj getting discoloured? What is the source of pollution? In 1993, neeri blamed it on acid rain, which happens when sulphur dioxide (SO2) and nitrogen dioxide (NO2) particles in the air combine with fog droplets and water condensation.But the measurement of pH value—to gauge the acidity or alkalinity—of rainwater and the waste water after washing the Taj contradicted this theory.
As a result,the court orders culminated in the landmark judgement of 1996 that directed the closure of 292 small industries,including 168 foundries,if they did not relocate or switch from coal and coke to cng, a cleaner fuel.The Mathura Oil Refinery, which started operations in 1982 and was found emitting high levels of SO2,was asked to switch to gas fuel.The order led to the closure of most of the small industries and almost all foundries in Agra in 2001.The Mathura Refinery switched to cng in phases by 2005.
At the time of the judgement, the court’s prime concern was SO2 emissions, which, it feared, could lead to acid rain and damage the marble surface of the mausoleum.The judgement also noted that “soot in itself is not harmful but that with tar it acts as a soiling agent”and that absorption of acidic gases is also enhanced by the presence of soot.The judgement quoted views of two foreign experts who said suspended particulate matter and dust were causing the marble to appear yellow.
Pursuant to court directions, the Union government and the Agra administration took a number of steps to clean the air in the Taj Trapezium Zone. Now cng is the fuel of choice in the zone, no vehicles are allowed within half-a-kilometre of the Taj Mahal, and a green belt is under development around the monument to filter out pollutants.
The iit-Wisconsin-Georgia study suggests that it is not acid rain,but black and organic carbon that is the cause of the problem.The source is incomplete combustion. Black carbon comes from diesel vehicles and brick kilns, and organic carbon from biomass burning.This would mean that the orders of the Supreme Court that would have reduced pollution from these sources have not
been implemented or that there is something new and different that needs to be addressed. Already, based on this study and a little more information, the city administration is rushing to close down petha (sweet made from ash gourd) units as these use coal and wood (see ‘Man v monument’, p42). Is this going to be the solution? Is this even the problem?
Key indicators down
In 2000, the Supreme Court had directed the Central Pollution Control Board (cpcb) to set up four monitoring stations to check ambient air pollution.By 2013,the city added four more stations, including one operated by asi in the Taj Mahal complex and three by the Uttar Pradesh Pollution Control Board.
neeri has analysed pollution data for the past nine years in its December 2013 report on a comprehensive environmental management plan for the Taj Trapezium.
It has found dramatic reduction in key pollutants SO2 and NO2 at the Taj Mahal between 2002 and 2012.The biggest difference is seen after 2005,when cng was introduced in the city.The level of PM10 at the Taj was significantly lower than at Nunhai, an industrial area outside the city, but was still two times the permissible standard of 60 μg/ m3 (see ‘Cause of concern’, p29).
In other words,pollution has definitely reduced in the city and more importantly,the levels are much lower in the vicinity of the monument.Now the question is whether these levels of particulate emissions are sufficiently high to cause discolouration of the marble.It is known that black carbon and organic carbon are a fraction of the particulate matter.
Clearly,the monument of love needs some more attention and care from us.We need to know the real cause of the problem so that the real answers can be found.
had ordered adequate drains and sewerage in Agra but only 17 per cent of the city is covered by sewerage