Taiwan's Lin wins India Open marred by 'dirty' conditions
Lin, 26, beat third seed Jonatan Christie of Indonesia 21-10, 21-18 in 38 minutes to clinch the men's crown at the Indira Gandhi Indoor Stadium in New Delhi.
In the women's singles final, world number one An Se-young of South Korea beat China's world number two Wang Zhi Yi 21-13, 21-11 to extend her domination on the court.
An has won six consecutive titles since the Denmark Open in October last year, compiling a 30-match winning streak.
However, the sheen was taken off the on-court action after players, including Denmark's Mia Blichfeldt, slammed the "dirty and unhygienic" playing conditions.
"Everyone is stressed and frustrated by the conditions we are being met with at a World Tour Super 750 event," she said in a social media post on Friday.
"At first, you try to laugh it off, but in the end, it is neither funny nor fair to the players or anyone participating in this event."
Blichfeldt, ranked 20, bowed out in the second round.
There were problems on most days of the tournament, including play being disrupted during a semi-final on Saturday when debris from a bird's nest fell on the court.
Bird droppings were also seen on courts, while TV pictures also showed a monkey making its way into the stands.
World number three Anders Antonsen of Denmark also withdrew from the tournament, citing "extreme" air pollution in Delhi.
The criticism will come as a blow to India's preparations for hosting the badminton World Championships in August, as well as the Commonwealth Games in 2030.
India, the world's most populous country, has also announced ambitions to host the 2036 Olympics.
Badminton Association of India (BAI) secretary Sanjay Mishra said the problems would be fixed before the World Championship.
"I know there are a few issues. But there's nothing that we can't manage," Mishra told local media.