Many European countries have issued more restrictions, while attempting to balance the economic fallout of a full lockdown.
It comes as the global total of COVID-19 cases passed 50 million on Sunday, according to Johns Hopkins University (JHU).
Portugal has become the latest European country to issue restrictions amid an aggressive second wave of the coronavirus pandemic.
"The situation that Portugal is going through is very serious. Everything must be done to control the pandemic," said Portuguese Prime Minister António Costa after President Marcelo Rebelo de Sousa issued a state emergency.
In 121 municipalities from Monday, there will be a curfew between 11 pm and 5 am and from 1 pm on weekends to curb the spread of the virus.
Portugal has had more than 170,000 confirmed cases since the beginning of the pandemic and like many other countries in Europe, has a rising incidence rate.
The United Kingdom entered its second national lockdown on 5 November and has been recording around 20,000 new cases of COVID-19 per day.
France is one of the worst-hit countries in Europe, with 125,414 new cases and 270 new deaths recorded in the last 24 hours according to JHU data.
Italy has instituted local lockdowns in four regions and a nationwide curfew in an attempt to stop the virus from spreading. Many countries have closed businesses or issued partial lockdowns.
As a result, the European Union recently cut its economic forecast, stating that the economy would not return to pre-pandemic levels until 2023.