This article has been published in partnership with Aditya Birla Group.

Every year on 5 June, World Environment Day prompts a familiar chorus of pledges, campaigns, and calls to action. But in the corridors of a government hospital in Malad, Mumbai, and along the walls of a navy school in the suburbs, the conversation has already moved well past pledges. 

Here, you might notice something unexpected: a dense, layered thicket of trees pressing up against the boundary, alive with birdsong, fluttering with butterflies, smelling faintly of wet soil even in the middle of summer.

These are not remnants of some forgotten wilderness. They were planted deliberately, sometimes in as little as 100 square feet of ground, by one man with a very specific conviction: that India's cities are not too crowded to have forests. They are just too accustomed to thinking small.

Subhajit Mukherjee, founder of Mission Green Mumbai and the Subhajit Mukherjee Foundation, has spent years making this case not through speeches or petitions but through soil preparation and sapling selection. He calls this the “no green without blue” philosophy, believing that planting trees without solving for water is what kills them. 

According to him, tree loss in India often has less to do with the number of saplings planted and more to do with the failure to build the water systems needed to keep them alive.

Subhajit has personally created over 40 dense urban pocket forests across Mumbai, Pune, and Chennai. Through citizen groups, institutional partnerships, and corporate social responsibility programmes in multiple cities, he has contributed to planting more than 3 lakh trees under this initiative. 

This makes him a true Force for Good hero, showing how one individual’s commitment can spark environmental change at scale. 

The projects he takes on individually range from 2,000 to 12,000 trees, with new installations happening almost every week. The model has also spread beyond Mumbai, replicated by citizens, schools, hospitals, and housing societies across India, who can access the full toolkit free of charge. 

Why India's cities desperately need this

The urgency behind Subhajit's work is not difficult to understand. Indian cities are warming faster than their rural counterparts, a well-documented consequence of dense construction, shrinking tree cover, and the proliferation of heat-absorbing concrete and asphalt.

Research published in 2024 found that urbanisation in India has enhanced city-level warming by as much as 60% compared to surrounding non-urban areas, and temperatures across major metros routinely breach 44–47°C during summer. Most Indian cities fall dramatically short of the 20–40% green cover that urban planners globally consider a baseline for liveable cities.

Mumbai, which Subhajit calls home and where most of his work is rooted, has a green cover of around 13% against the government-recommended 33%. The city's rapid development has consumed the open land that once allowed communities to plant trees at scale. 

"Mumbai has a lot of infrastructure development work going on," he tells The Better India, "and we do not have the space to do re-plantation." It is precisely this constraint that his pocket forest model was built to address.

‘We can now take walks during the day’

The difference this kind of greening makes is not abstract. At the General Hospital in Malad, Manoj, a senior pharmacy officer, describes what the campus looked like before Subhajit's team began working on it roughly three years ago. "It was a very dry area with only dead grass and trees that were not useful," he says. 

Today, pocket forests line the boundary walls and fill the spaces between buildings. They are watered entirely using the hospital’s........

© The Better India