Canister for containing an active agent

A canister for containing an active agent for allowing the active agent to interact with an environment of the canister, when the canister is closed, wherein

• the canister comprises:
• a canister body comprising a peripheral body wall defining an upper opening for inserting the active agent into the canister body, and
• a non-removable snap-on cap cooperating with the canister body so as to close the upper opening,
• wherein the cap comprises a peripheral skirt,
• wherein the peripheral body wall comprises a step formed between a first portion of the peripheral body wall, located adjacent to the upper opening, and a second portion of the peripheral body wall, located beneath the first portion, wherein the first portion is at least partially thinner than the second portion so as to form the step,
• wherein an inner shape of the peripheral skirt and an outer shape of the first portion of the peripheral body wall form a snap-on fit between the cap and the canister body wherein the cap at least partially laterally surrounds the first portion, and
• wherein a vertical extension of the peripheral skirt is smaller than a vertical extension of the first portion of the peripheral body wall so as to form a gap between the step and the peripheral skirt when the cap is snapped onto the canister body.