SHILLONG: Together with the rest of the world, the International Day for Preservation of Ozone Layer was observed in Tura today with day-long programmes, including tree plantations and various competitions for students. To mark the occasion, the Social Forestry Division, Tura, in collaboration with the Integrated People for Tourism and Conservation (IPTAC), NSS of Tura Government College and Don Bosco College organized an impressive function at the conference hall of Don Bosco College, here.