挤 works as both a verb (to squeeze/push) and adjective (crowded). 挤地铁 = squeeze onto the subway. 很挤 = very crowded. 挤牙膏 = squeeze toothpaste (also slang for dragging out information reluctantly).
culture
挤地铁 (squeezing into the subway) is a daily reality in Chinese megacities. Beijing Line 13 and Shanghai Line 9 during rush hour are legendary. 人挤人 (rén jǐ rén) = people pressing against people.