French workers angry over proposed changes to retirement rules are halting high-speed trains, disrupting electricity supplies and taking to the streets Thursday in a day of nationwide strikes and protests seen as a major test for Emmanuel Macron and his presidency.

French workers would have to work longer before receiving a pension under the new rules – with the nominal retirement age rising from 62 to 64. In a country with an aging population and growing life expectancy where everyone receives a state pension, Macron’s government says the reform is the only way to keep the system solvent.

Unions argue the pension overhaul threatens hard-fought rights, and propose a tax on the wealthy or more payroll contributions from employers to finance the pension system. Polls suggest most French people oppose the reform.

More than 200 rallies are expected around France on Thursday, including a large one in Paris involving all France’s unions.

Police unions opposed to the retirement reform are also taking part; those who aren’t protesting are bracing for potential violence if extremist groups join the demonstrations.

A majority of trains around France are cancelled, including some international connections, according to the SNCF rail authority. About 20% of flights out of Paris’ Orly Airport are canceled and airlines are warning of delays.

Electricity workers pledged to reduce power supplies as a form of protest, and some 70% of preschool and primary school teachers said they would refuse to work Thursday, according to French media reports. Even high school student unions are expected to join the protests by blocking access to some schools.

The French government is formally presenting the pension bill on Monday and it heads to Parliament next month. Its success will depend in part on the scale and duration of the strikes and protests.

Protracted strikes met Macron’s last effort to raise the retirement age in 2019 and he eventually withdrew it after the COVID-19 pandemic hit.