Passengers who use public transportation in Istanbul will require the country's coronavirus contact tracing HES code as of Friday.
According to a circular issued by Turkey's Interior Ministry, the cards used for subways and public buses will be paired with the unique code that will determine a person's likelihood of having caught the COVID-19 infection.
Those transportation cards in Istanbul that are not matched with the HES code will be invalid as of Friday.
High-risk passengers will not be allowed to board.
There are over 34 million Istanbulkart users, according to the municipality data.
*Writing by Merve Aydogan in Ankara