In the dense smog that engulfed India ’s capital early this month, a baby named Vaishnavi gasped through the night. Inside the concrete room that her father and mother rent for $20 a month, they took turns staying up, laying a hand on her rib cage, feeling it move up and down. Her coughing fits became so violent that she vomited, milk mixed with ropes of sputum. Three times they thought she would not survive until morning. Twenty miles away, inside an elegant, high-ceilinged house in an elite neighborhood, a 4-year-old boy named Mehtab was also struggling to fill his lungs with air. His mother, heavily pregnant, sat beside him, administering corticosteroids through a nebulizer mask once an hour. But once an hour wasn’t enough. Mehtab’s father fought waves of panic as they waited for the sun to rise. The boy looked, to him, like a […]