The European Commission said the Covishield vaccine, produced by the Serum Institute of India in collaboration with AstraZeneca of the UK, had failed to be licensed by the European Medicines Agency and could restrict travellers travelling into the EU who had received the vaccine.

The European Union's new crown digital certificate came into force on July 1. Travelers in the European Union and other Schengen countries such as Norway, Iceland, Switzerland and Liechtenstein will be allowed to travel with a vaccine approved by the European Medicines Agency or with a negative test certificate.

At the same time, EU Member States have the right to decide on their own whether to allow visitors to enter the country with vaccines approved by the World Health Organization, and Covishield vaccine has been listed by WHO as a vaccine for emergency use.

Some people in the UK have been vaccinated against AstraZeneca, which is made in India, the BBC reported. Five million of the 100 million doses of AstraZeneca ordered in the UK, which are widely believed to be the same product as those made in Europe, were imported from India.

But as the European summer holidays get under way, there are concerns among UK travellers about how different versions of the AstraZeneca vaccine will be treated in the EU. Only a handful of the 27 European Union member states are currently allowing both versions of the vaccine into the country, according to the report.

The European Commission is working closely with countries to develop a coordinated approach to the vaccine screening process, European Commission health spokesman Stefan Deckelsmaker said at a press conference on Monday