Indira Gandhi was elected Prime Minister with a decisive majority in 1971.
The Shillong Accord took place in 1975.
Emergency was declared on 25 June 1975. It led to the arrest of many of India’s leaders. The Emergency is a well documented period in Indian history e.g. the compulsory sterilisation program of the years, the killings at Turkman Gate, the Rajan case and the incarceration and death of Snehlata Reddy.
The lifting of Emergency in 1977 was followed by a general election which led to a new government, the first time Congress lost power after Independence. Parliament was however dissolved in 1979 and Indira Gandhi was back as Prime Minister in 1980. The same year Sanjay Gandhi was killed in an aircrash.
The Mathura rape case in 1972 led to amendments in laws pertaining to rape, albeit only by 1983.
India won the hockey World Cup in 1975.
Amar Chitra Katha’s major titles date back to the 70s.
Apparently Panna Dossa was the big cheese of sari fashion in the 1970s. She started a sari store called Kalindi and designed saris for Indira Gandhi (opinions vary wildly on her as a politician but sartorially she rarely put a foot wrong) but I can’t find much else on her.