In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.

The Aarey forest, a verdant strip that lies at the heart of India's bustling Mumbai city, is often referred to as its last green lung. But now, locals say, it's under threat from encroachment. BBC Marathi's Janhavee Moole reports.
Aarey forest: The fight to save Mumbai's last 'green lung'