An aerial view of Evanston. [City of Evanston]

The Evanston City Council on Monday night delayed by two weeks a vote on a measure to require large buildings to become more energy efficient and eliminate their carbon emissions by 2050, with some council members citing too many unknowns about the effects of the ordinance. 

Some also took issue with last-minute tweaks to the legislation proposed by sponsor Councilmember Jonathan Nieuwsma.