New measures to curb the spread of Covid-19 in Blackburn with Darwen have been introduced after a spike in cases.
For the next month, people living within the Lancashire authority must observe the rules in a bid to avoid a Leicester-style local lockdown.
The new measures include tighter limits on visitors from another household, and officials have called on people to bump elbows in place of handshakes and hugs.
Mass testing began at the weekend after 61 new cases sprang up within a week.
Lockdown 'real possibility'
Residents are being told to wear cloth face coverings in all enclosed public spaces, including workplaces, libraries, museums, health centres and hair and beauty salons.
Blackburn with Darwen's public health director, Prof Dominic Harrison, also called for people only to bump elbows with anyone outside their immediate family.
He said public protection advice for small shops was being stepped up to ensure social distancing was being observed.
Targeted testing is taking place in the borough, and residents have been told they do not need to have symptoms to be tested.
Prof Harrison said: "These steps will help and we are appealing to everyone in Blackburn with Darwen to follow them to protect themselves and their loved ones.
"If we don't, a local lockdown, like in Leicester, becomes a very real possibility."
He said increased testing would mean a "rise in the number of cases" in the next seven to 10 days.
If rates were continuing to rise after two weeks, he said, the authority would "have to consider reversing some of the national lockdown lifting measures locally".
This would be done "one by one until we see a reversal in the current rising trend," he said.
"It's up to everyone to make sure we don't have to do that."
He said there would also be "targeted work" after a rise in infections within the South Asian community - in particular "cluster infections" among families living in small terraced houses.
When "one person gets infected in a multi-generational household, all the household members are getting infected", Prof Harrison said.
How Blackburn with Darwen compares
Figures show Blackburn with Darwen recorded 47 new cases per 100,000 in the week ending Saturday, up from 31.6 the previous week.
In Leicester, where a local lockdown has been imposed, the rate has risen from 115 per 100,000 to 118 over the same period.
But this is still down from 152.2 in the seven days to 27 June.
Based on figures released on Tuesday, Pendle in Lancashire currently has England's second-highest rate of new cases for the week, rising from 14.2 per 100,000 to 76.6 in the week to 11 July.
Data obtained via NHS dashboard
Information videos are being produced in English, Urdu and Gujurati to spread the message in the former mill town.
Council leader Mohammed Khan said the authority was working to spread the message that "life cannot go back to normal just yet, and we must all make sacrifices to avoid a local lockdown".
"We are doing everything we can to get a grip on the virus, and we need everyone in Blackburn with Darwen to pull together to help us," he said.
"Please continue to do your bit to stick to the rules to protect yourself and your family."