Rampant construction and poor compensatory plantation are taking a toll on Kolkata's environment. And it has probably never been as stark and quick as in the last year. The city's green cover now stands at a dismal 5%, which is way below the requirement of 15% for metros. In the last 12 months, Kolkata and its adjoining areas have lost more than 5,000 trees to developmental projects, unauthorized chopping and natural causes. The loss is unprecedented, says the forest department. This could have brought the cover further down and has pushed up the carbon count by an alarming 5,500,000 kg per year, the department admitted. The impact of this loss would be felt in the coming years, feel environmentalists. And it could be irreversible, given the sporadic and unplanned compensatory plantation in Kolkata. The figures confirm the fear. As much as 95 lakh tonnes of carbon are generated in Kolkata from vehicular emission every year. Since each full-grown tree can absorb around 1,100 kg of carbon a year, a loss of 5,000 plants means 5,500,000 kg more carbon in the city's atmosphere. In comparison, the green cover in Delhi and Mumbai are much higher. While the Capital has a cover of 19.09%, Mumbai was marginally behind at around 18%. The national average stands at a healthier 19.49%. On the whole, orest cover has been on a steady decline since 1981 in Andhra Pradesh, Assam, Bithe dense forest in the country has increased by 1.88 per cent, but the area under open forest has declined by 2.55 per cent. However, the trend in some states is at a variance with the national trend. Fhar, Haryana and West Bengal. On the other hand, states like Arunachal Pradesh, Nagaland, Manipur and Sikkim have shown a decline in their forest cover in the latest assessment.