New Delhi, Air pollution may be altering the very chemistry of Delhi’s roadside leaves, affecting their ability to produce food and retain water, with trees in highly polluted areas showing greater physiological stress than those in less polluted locations, a study has found.
The study-Urban Air Quality and Pollution Tolerance of Roadside Trees in Delhi: An TI Approach-also found differences in the amount of water retained by leaves, an important factor in maintaining their biological and biochemical functions.
The study examined seven tree species across four locations in Delhi – the highly polluted areas of Anand Vihar and NTPC Badarpur, and the relatively less polluted areas of Lutyens’ Delhi and the Indian Agricultural Research Institute in Pusa – to assess how pollution levels and seasonal variations affected their physiological properties. Published in BIO Web of Conferences, the study discusses this process as one of the ways pollution can affect plants, although it assessed the trees through biochemical indicators rather than directly measuring cellular damage. The researchers noted that leaf pH can be associated with a plant’s response to air pollution, with lower values linked to greater sensitivity in previous studies. The researchers used chlorophyll content, ascorbic acid levels, leaf pH and relative water content to calculate the Air Pollution Tolerance Index , a measure used to assess a plant’s ability to withstand air pollution. The study examined seven species neem, devil tree, peepal, arjun, Ficus infectoria, amaltas and false ashoka across the four locations and assessed their physiological properties over four seasonal sampling periods.
Differences were also observed in leaf pH, with values of 5.78 at Anand Vihar and 5.91 at NTPC Badarpur, compared with 6.45 in Lutyens’ Delhi and 6.05 at Pusa. Among the seven species examined, neem recorded the highest TI score of 14.52, followed by amaltas at 13.50 and false ashoka at 13.37. Arjun recorded a score of 13.13, while Peepal and Ficus infectoria recorded 12.27 and 12.39, respectively.
