Under Ontario law, a landlord must have a proper legal reason to evict a tenant. Reasons for eviction include, but are not limited to, frequently paying rent late, damage to the premises, and disrupting other tenants. Under the Residential Tenancies Act, landlords may include a no-smoking clause in any lease. However, they must develop a building-wide no-smoking policy and ensure that all tenants and visitors follow the policy and enforce it throughout the property. If there are tenants already living in the building before introducing this policy, the landlord cannot prevent them from smoking. If a tenant signs a lease with a no-smoking clause and they later smoke, landlords cannot evict them based on their broken promise. To evict a tenant for smoking, they must prove that the smoke damaged the property or interferes with the environment of other tenants, typically through second-hand smoke. With proper evidence, the landlord must present adequate notice to the tenant and apply to the Landlord and Tenant Board for an order to evict the tenant.