Hi @Aayushi Srivastava - if this issue is occurring on Chrome but not on an incognito tab, my hunch is you've got an extension causing this issue. Can you try disabling all your extensions and see if that fixes the problem? If it does, I'd try reenabling your extensions one at a time to pin point which one is causing the issue here.
Welcome to Community !
Can you please check out this similar issue addressed here https://community.atlassian.com/t5/Trello-questions/all-my-lists-and-cards-shrunk-in-size-and-are-way-too-small-now/qaq-p/1555716