Greenpeace India’s scientific analysis has revealed high concentrations of heavy metals inside classrooms of different schools across Delhi between October-November. A report released showed the samples collected and tested inside the classrooms of having alarming levels of heavy metal presence on days when PM 2.5 concentrations were higher than the prescribed levels. The study was conducted to decode constituents of PM 2.5 from the collected sample. PM 2.5 concentrations from monitors installed inside the classrooms showed indoor air quality five times above the Indian safety limits, and as much as 11 times above the World Health Organisation’s safety limits, taking the average to 293 (µg/m3). The same samples when tested for elemental composition of PM2.5 showed dangerous levels of heavy metals such as Arsenic, Cadmium, Lead and Nickel which are carcinogenic and detrimental to health.