“It’s one thing to continue to have tons of people living day by day, and another to have thousands dying of this every day,” said Jesús Silva Herzog, a professor of government at the Tecnológico de Monterrey, a university in Mexico.

On Tuesday, Mexican officials, citing a shift in the outbreak, announced a stricter set of protocols, canceling events drawing more than 100 people and calling for the suspension of employment requiring workers to commute to an office.

Over the weekend, the López Obrador administration began urging Mexicans to stay home. And late Monday, officials tightened restrictions even further, ordering the shutdown of all non-essential activities. But many Mexicans cannot work from home, or forgo work for weeks.

Mr. Meneses, 43, who has sold hamburgers and hot dogs from his cart for 19 years, said he was less worried about contracting the virus than he was about the financial effects of the pandemic.

His business has already cratered. His sales are down about 50 percent from two weeks ago and still falling.

If the authorities force street vendors to shut down, Mr. Meneses said, he does not know what he will do to support his wife and three daughters. Maybe start pawning possessions, he said.

The family has no health insurance.

“For us, it’s a luxury to get sick,” he said.

In some countries in the region, when governments have tried to impose restrictions to fight the virus, poor workers have rebelled — and been met with force. In Peru, more than 21,000 people, including street vendors and other laborers in the informal economy, have been detained for not complying with the government’s orders to stay at home.