New Delhi, March 27 -- In 2017, the Hall of Industries and Nations and Nehru Pavilion at Pragati Maidan in Delhi were demolished. These modernist structures had been built on the occasion of India's 25th independence anniversary. They were technologically advanced for their time and symbolic of the spirit of a fledgling nation. But heritage, according to Delhi's Heritage Conservation Committee, must be at least 60 years old. The Delhi high court ruled that the structures did not make the cut, pav ing the way for the government to pull them down. Similar cut-offs in age are applied by other heritage bodies. For the Archaeological Survey of India, a monument must be at least 100 years old to count for protection. For the Directorate of Arch...