Hanoi, the capital city of Vietnam, currently in the period of strong economic development, was ranked among the top polluted cities in the world. Cities account for more than 70 percent of global greenhouse gas emissions and consume two-thirds of the world’s energy; they are ideally positioned, therefore, to drive local action.

Tropical and sub-tropical forests play an important role as carbon sinks in the global carbon cycle. On average, one hectare of forest can sequester 460 kg of carbon daily. Trees reach their most productive stage of carbon storage at about 10 years at which point the forest is estimated to absorb 12 tons of carbon daily. The green lungs with an area of about 26 hectares and thousands of trees, would act as an important carbon sink for Hanoi.