Afternoon Update: Optus outage causes nationwide frustration; ketamine use hits record peak; and global wine production falls

A nationwide Optus outage has affected millions of customers, hospitals and businesses, and brought Melbourne’s entire train network to a halt. Photograph: Reuters

Good afternoon. Optus is gradually restoring services after a nationwide outage left millions of customers and businesses without mobile and internet access.

The cause of the outage remained unclear, the Optus chief executive, Kelly Bayer Rosmarin, said. Hospitals across the nation were affected, while Melbourne’s entire train network was brought to a halt due to the outage.