Security was beefed up in the district though there were no reports of any untoward incidents so far.
The victims were remembered by their near and dear ones and others who lit up candles before their portraits at events held in different parts of the district.
On May 22, 2018, an anti-Sterlite protest turned violent with the agitators fighting pitched battles with the police, prompting the latter to open fire.
Thirteen people were killed in the firing on May 22-23 last year.
The protesters were demanding the closure of Vedanta's Sterlite Copper unit in Tuticorin over pollution concerns.
The incident had triggered widespread outrage and criticism against the Tamil Nadu government even as the ruling AIADMK later announced a "permanent" closure of the copper smelter plant here.
Leaders of various political parties and Tamil groups have expressed solidarity with the victims and the anti-sterilite movement.