To expel in an upward direction. You can't see far into the distance with all of the smoke being belched up from the factories along the river.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
belch something up
to cause the release of something that goes upward. The fire belched flames and smoke up. The volcano belched up clouds of poison gasses.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.