Sergio litigates at both Trial Courts as well as the High Court. He is particularly passionate about Environmental Justice Cases and the Criminal Justice Initiative. He had represented Tenzing Tsundue and other students from Friends of Tibet, who were arrested for protesting against the visit of the Chinese President, and was successful in securing their bail. Sergio also works on cases of custodial violence by police personnel. In another matter, Sergio successfully represented local farmers against the building of a resort and golf course which was preventing locals from accessing their cashew plantations.