Western Australia premier, Mark McGowan, makes the announcement
This comes after two persons caught the virus (UK variant) while in Perth hotel quarantine, from a couple staying in an opposite room. The couple in question had arrived in Perth from India and were infected with the UK variant of the virus.
The lockdown here is to prevent any major spread within and outside the city, though three days may be somewhat moot depending on how you look at it.
Of note, a person in Melbourne has been found to have contracted the virus earlier today after having returned from the same quarantine hotel in Perth. Said person flew back to Melbourne on Wednesday after having spent two weeks quarantining in Perth.