NIVEDITA BHATTACHARJEE and ANURON KUMAR MITRA INDIA’S main opposition leader Rahul Gandhi warned on Friday that unless the deadly second COVID-19 wave sweeping the country was brought under control it would devastate India as well as threaten the rest of the world. In a letter, Gandhi implored Prime Minister Narendra Modi to prepare for another national lockdown, accelerate a countrywide vaccination programme and scientifically track the virus and its mutations. Gandhi said the world's second-most populous nation had a responsibility in "a globalised and interconnected world" to stop the "explosive" growth of COVID-19 within its borders. "India is home to…