Environment Day has been observed annually since 1991, but there is fresh impetus this year for introducing measures to wean consumers off plastic bags.
Stores are being urged to stop bagging purchases in plastic and instead to give away cloth bags or encourage customers to bring cloth bags with them.
Hospitals are also being asked to dispense medicine in cloth rather than plastic bags.
One survey found that Thais on average produce 1.14 kilograms of trash per day, totalling 74,000 tonnes across the nation.
The ministry’s Department of Environmental Quality Promotion will on Tuesday host a commemorative event in Impact Arena Hall 9 with the theme “Doing good deeds with your hearts, minimising threats to the environment”.
The aim is to discourage use of plastic and Styrofoam, said department chief Suriyakul Na Ayutya.
People can also donate cloth bags at shopping malls and the department's event on Tuesday, so that the cloth bags can be donate to hospitals nationwide to bag medicine packs for patients.