A rule requiring international travellers landing at Ontario’s largest airport to take a COVID-19 test came into effect Monday amid growing concern over vaccine deliveries and new reported cases of contagious COVID-19 variants. The Ontario government implemented the measure at Toronto’s Pearson International Airport as a stopgap while waiting for a similar federal program announced last week to get off the ground. Premier Doug Ford has praised Ottawa for announcing a new testing plan but said Ontario will conduct its own traveller testing until the federal program kicks in. Canada’s chief public health officer said new COVID-19 cases have been trending downward across the country in recent days, but she is warning it’s crucial to keep strong measures in place to maintain the tendency. “With still elevated daily case counts and high rates of infection across all age groups, the risk remains that trends could reverse quickly, and some areas …