India's tiger conservation body said 126 of the endangered big cats died in 2021, the most since it began compiling data a decade ago.
The previous highest number of deaths per year before the National Tiger Conservation Authority (NTCA) began compiling data in 2012 was in 2016, when 121 perished.
India is home to around 75% of the world's tigers.
It is believed there were around 40,000 tigers at the time of independence in 1947 but hunting and habitat loss has slashed the population to dangerously low levels.
In 2010, India and 12 other countries signed an agreement to double tiger numbers by 2022.
Last year, the government announced that it had reached the target ahead of schedule, with an estimated 2,967 tigers in 2018 versus a record low of 1,411 in 2006.
The number is still lower than 2002 when the tiger population stood at around 3,700 but Prime Minister Narendra Modi hailed it as a "historic" achievement.
The 2018 data may have been partly down to the survey size, however, which used an unprecedented number of camera traps to identify individual tigers using stripe pattern recognition software.
Over the past decade the biggest reason for deaths recorded by the NTCA was "natural causes", but many also fell victim to poachers and "human-animal conflict".
Human encroachment on tiger habitats has increased in recent decades in the country of 1.3 billion people.
Nearly 225 people were killed in tiger attacks between 2014 and 2019, according to government figures.
Kartick Satyanarayan, founder of Wildlife SOS, told AFP deaths due to human-animal conflict were driven by "the fragmentation of the tiger's natural habitat."
"Tigers range over large jungle areas and find it impossible to migrate to other forests without crossing human habitations, increasing chances of conflict," he said.
Critics say that the government has also loosened environmental regulations for projects including mining.
Satyanarayan also said increasing demand for tiger skins and use of tiger body parts in traditional Chinese medicine were some of the major reasons for poaching.
The government has made efforts to manage the tiger population better, however, reserving 50 habitats across the country for the animals.
Conservation group WWF said in a report last year that tigers were making a "remarkable comeback" in much of South Asia as well as Russia and China.
But tigers were still under threat from poaching and habitat destruction and the wild animal populations had fragmented, increasing the risk of inbreeding, the WWF said.
"This has reached critical levels in much of Southeast Asia, where a snaring crisis is decimating wildlife, including tigers and their prey," the group said.
The Indian government's 2020 report meanwhile warned that many tiger populations were confined to small protected areas.
Many of the "habitat corridors" enabling the animals to roam between these areas were at risk due to human activity and development, it warned.