India, Sept. 9 -- Greening cities has become one of the defining themes of urban planning in India. Across the country, municipalities proudly announce plantation drives, highlight the number of saplings planted, widen medians to accommodate trees, and carve out green belts to curb dust. The sight of tree-lined avenues and landscaped parks is undoubtedly a relief in an era of choking smog and record-breaking heat. Yet, behind this enthusiasm lies a reality we are often reluctant to acknowledge: not all greenery is necessarily good for health. Poorly chosen or badly maintained vegetation can aggravate respiratory illnesses, heighten allergies, and in some cases, worsen the very pollution it was intended to mitigate. If India's urban spaces a...