Why did Sourav Ganguly take off his shirt and wave it at Lord's balcony 22 years ago?

Ex-India captain Sourav Ganguly took off his shirt and waved it at Lord's balcony on July 13, 2002 after leading India to NatWest Series final win against England. Ganguly revealed it was in response to ex-England all-rounder Andrew Flintoff taking off his shirt and running at Wankhede Stadium after helping England tie six-match ODI series 3-3 on February 3, 2002.