Pausing Unrelenting Markups on Petroleum Act of 2021 or the PUMP Act of 2021 This bill suspends the excise tax on gasoline other than aviation gasoline during a specified holiday period. The bill defines holiday period as the period beginning on the enactment date of this bill and ending on the latest of (1) the first date after enactment on which the public health emergency declared for COVID-19 is no longer in effect, or (2) 180 days after enactment.