The 29-year-old, who top scored for Orient last season with 13 goals, was offered a new deal at Brisbane Road but has instead opted to join Kerala Blasters, coached by former England Under-21 manager Peter Taylor.
He told the O’s website : “I have enjoyed my 18 months with the club and I have some great memories over the course of that period.
“I would like to take the opportunity to thank all the fans for their support they have given to me and the club during my time here. They were very welcoming from the minute I joined and I can only thank them for that.
“This will be a new challenge for me over in India and a completely new environment, country and culture, but one I look forward to.”