NEW DELHI : A fresh batch of ink is being used in the COVID-19 quarantine stamp for international passengers at the Delhi international airport after a Congress leader complained about pain and itchiness due to the chemical used in it, said senior government officials on Monday."After the complaint, the Delhi state authorities have started using a fresh batch of ink to stamp incoming international passengers," said one of the officials.As per rules, all international passengers have to undergo seven days of institutional quarantine followed by seven days of home quarantine post arriving in Delhi.However, certain categories of passengers like those with COVID-negative certificates from a test done 96 hours prior to the journey are exempted.