linguistic:voice_change, stylistic:tone
Air pollution

Pollution is a major concern in Patna. According to the CAG report, tabled in the Bihar Legislative Assembly in April 2015, respirable suspended particulate matter (RSPM) level (PM-10) in Patna was 355, three-and-a-half times higher than the prescribed limit of 100 micro-gram per cubic metre, primarily due to high vehicular and industrial emissions and construction activities in the city. In May 2014, a World Health Organization survey declared Patna the second most air polluted city in India, only after Delhi, with the survey calculating the airborne particulate matter in the state capital's ambient air (PM-2.5) to be 149 micro-grams, six times more than the safe limit, which is 25 micro-grams. Severe air pollution in the city has caused a rise in pollution-related respiratory ailments, such as lung cancer, asthma, dysentery and diarrhoea. The dense smog in Patna during winter season results in major air and rail traffic disruptions every year.