The second most populous country in the world will have to vaccinate millions upon millions of its people against the coronavirus. India has yet to approve a vaccine that can cover the second largest population on Earth. And when it does, getting this task completed will be perhaps one of the biggest logistical exercises the world has ever seen. So how will India do it? Experts say India’s universal immunisation programme, already the largest in the world, offers a starting point. There is considerable medical infrastructure already in place. But can it be used to deliver a future coronavirus vaccine? Nimisha Jaiswal and Sharique Ahmad went looking for answers.