France's rail network has been severely disrupted, as a wave of strikes against President Emmanuel Macron's labour reforms gets under way, writes bbc.com.

The start of the strike has been dubbed "Black Tuesday", but the action will spread over three months, affecting two days in every five.

Staff at state railway SNCF are leading the strike, but the energy and waste collection sectors are also affected.

The unrest presents Mr Macron's biggest challenge since his election last May.

How is the strike taking hold?

With the four main rail unions observing the strike, services have been severely curtailed. Some 77% of SNCF drivers are on strike, and 48% of all staff.

Only one in eight high-speed TGVs are scheduled and only one in five regional trains.

Commuter lines into Paris have also been slashed and bus services have been hugely overcrowded. Some stations were crammed for the few trains available, others were deserted.

The website that measures car traffic around the capital recorded about 420km (260 miles) of jams at rush hour.

• How this could affect your train journey (in French)

International services are more sketchily affected. Eurostar has 75% of trains running and the Thalys services to Belgium, the Netherlands and Germany is almost normal, but there are no services to Spain, Switzerland or Italy.

Employees of Air France, who are demanding a 6% pay rise, are into the fourth day of industrial action. The airline is operating 75% of its flights.

Unions have also called out all rubbish collectors, to push for the creation of a national collection service and better retirement options. The capital, the north and east, along with Marseilles could be worst affected.

Energy sector unions have also called strikes to demand, among other things, an end to the liberalisation of the energy markets and a review of deregulation.

Can Macron face down the strikers?

Analysis by the BBC's Hugh Schofield in Paris

There are three reasons why President Macron feels relatively optimistic about the rail strike.

First, unlike in the last massive (and successful) general strike in 1995, this time there can have been no mistaking the government's intention to reform. Neither the public nor SNCF staff can pretend the planned changes come out of the blue. They are clearly part of the broad reform agenda for which Mr Macron was elected.

Second, there is far less automatic sympathy for the SNCF than there used to be. The level of rail services has declined sharply, especially for commuters, who are as a result more open to calls for reform.

Third, new options have opened up for commuters. There is home-working; car-pooling; expanded coach services. This should make it easier for workers to get round the inconvenience.

All that said, these will be tense weeks for the government. Nerves are going to fray. People will get angry. Daily life will not be easy. In these circumstances, plans can go badly awry. A wrong move and public opinion could easily shift back behind the striker.

What is the strike about?

SNCF workers enjoy generous conditions, including automatic annual pay rises, early retirement, 28 days of paid annual leave and protection from dismissal. Their close relatives are also entitled to free rail tickets.

But the rail unions feel the action is wider than that, and it will be a major test of union clout.