"They say they're going to raise the price of gasoline and electricity ... and I only make 100 pesos ($5) per day," said Alejandro Montes de Oca, a protesting janitor, who pays 40 percent of his wage on public transportation each day.

The gasoline price had stayed somewhat stable for nearly 25 years, increasing gradually to control inflation, though heavily subsidized at times.

The federal government approved an energy reform in 2013 to attract foreign investment, increase oil and gas output and allow Pemex -- the state oil monopoly -- the ability to partner with other petroleum companies to explore and drill in the deep waters of the Gulf of Mexico.

President Enrique Pena Nieto told the country in a Jan. 5 message that gasoline subsidies -- as high as $20 billion in 2008 -- only benefited the rich, while the revenue from raising prices at the pump funded social programs. Mexico also imports half its gasoline, paying in dollars at a time the peso has plunged -- partly due to President-elect Donald Trump's threats at slapping tariffs on Mexican-made imports into the United States.

Observers attribute the outrage to a confluence of factors, including a belief among the public that higher gasoline prices cause the cost of other necessities to rise, along with perceptions of corruption in government and politicians living lavishly on public money.

"We are all called to act responsibly ... particularly the upper bureaucracy and political class of immorally high salaries and inconceivable benefits in a weak country of 2 percent annual economic growth and half the population living in poverty," read an editorial published Jan. 8 in the Archdiocese of Mexico City publication Desde la Fe.

"People are tired of this. That's why there is such indignation and fury."