We investigate the impact of dedicated loading-unloading zones (LUZs) in emerging markets, focusing on their effects on air quality and noise pollution. We conduct a field experiment in downtown area of Zapopan, Mexico. We use a quasi-experimental difference-in-difference approach to analyze changes in air quality and noise pollution before and after implementing the dedicated LUZs. The results indicate a significant reduction of up to 3.55% in CO2 levels in the mornings and a 14% decrease in noise following the establishment of LUZs. Moreover, insights into the composition of companies involved in last-mile distribution reveals a predominant reliance on micro and small businesses, often utilizing personal vehicles for cargo transport, with a significant portion of freight vehicles being over a decade old. We contribute to the existing literature by providing evidence of the impact of LUZs on mitigating negative externalities associated with last-mile operations, particularly in a developing city.