Some of my earliest memories of Bengaluru, where I spent my summer holidays, are of looking up in wonder at the towering canopy of trees in Cubbon Park. Even in the height of summer, Bengaluru could be cool enough to require a light jacket. Today, the iconic Cubbon Park, the pride of the city I now call home, is under threat. So is Lalbagh Botanical Garden, another of the city’s iconic green spaces, with roots stretching back more than 250 years.On a Sunday morning in Bengaluru last month,...