<prompt> Translate the following text to EnglishKatika maeneo mengi ya mijini, uzalishaji wa NOx kutoka kwa magari, malori, na mitambo ya umeme huchangia hali ya mawingu ya kahawia wakati wa majira ya baridi kali.  <response>: In many urban areas, NOx emissions from cars, trucks, and power plants contribute to winter time brown cloud situations. 