The neglected issue of drowning   It’s been 17 years but 77-year-old Admiral Purushottam Dutt Sharma remembers the day in November 1997. “It always brings a lump to my throat,” he says. At 9 a.m. on November 19, 1997, a bus meant for 55 children but packed with 75, crashed over the rails of the Wazirabad bridge across the Yamuna in Delhi. It fell into the river and came to rest on a sandbank, windows above the water. Some of the students in the bus were in shock; some so