The Syro-Malabar Catholic Archeparchy of Trichur-Palayoor, in Thrissur District of Central Kerala, India, with nearly half a million Syro-Malabar Catholics now, used to be the largest Catholic diocese in India when it included the Syro-Malabar Catholic Diocese of Irinjalakuda until 1978 and Syro-Malabar Catholic Eparchy of Palghat until 1973. Wikipedia