Excise officials arrested one person with alleged possession of 21 kg of ganja near Pravachambalam late on Friday.
The police identified the accused as Shijaam of Vellayani. The accused is an habitual offender, sources said.
In another case, two West Bengal natives, Sajal Das and Sabuj Mandal, were apprehended at the Amaravila excise check-post allegedly with 4.02 kg of ganja. The duo were travelling on a bus coming to Thiruvananthapuram.