TORONTO—A stay-at-home order takes effect across Ontario today in response to worsening COVID-19 trends. Premier Doug Ford announced the move yesterday, saying it was prompted by a surge in cases driven by more infectious variants. Stores that sell goods such as groceries, cleaning supplies and pharmacy products can remain open but only to sell essential items. Non-essential retail can open for curbside pickup or delivery only. The province is declaring the third state of emergency since the start of the pandemic to invoke the new measures. The changes come after a month-long shutdown announced last week was criticized as too weak to address the third wave of infections.