According to the passage it's only since the early 1970's that in India, _______.

India is thought to have had 40,000 tigers at the turn
of the century, but the maharajas killed them in their
thousands. By the time such hunts were banned in
India in 1972, there were fewer than 2,000 tigers left.
India, with 60 percent of the world's tigers, is warning
that the animal is headed for extinction. Officials say
that poachers are the tigers' main predator - the
animals' bones are ground into potions in China and
other Asian countries. Conservationists say the real
threat to the tiger is governmental reluctance to halt
the development destroying the tigers' natural
habitat. While the tigers in India's wildlife sanctuaries
are thriving, those roaming elsewhere- half the tiger
population - are competing for space with dams,
roads, and industry. Over the past 25 years, India's
tiger habitats have shrunk by half.