The accident occurred near Shahwajpur Dor village under the Gajraula Kotwali police station area when visibility dropped sharply due to heavy fog.
Poor visibility resulted in a multi-vehicle pile-up involving around 10 vehicles, as drivers were unable to see vehicles ahead in time to avoid collisions.
Police teams and ambulances rushed to the spot and shifted all injured persons to a nearby hospital for treatment.
Officials said traffic movement on the highway was severely disrupted following the accident, creating chaos for commuters.
Authorities later deployed cranes to remove the damaged vehicles and gradually restored traffic flow.
The condition of the injured is reported to be stable, and treatment is ongoing.
Police have initiated an investigation into the incident, while motorists have been advised to exercise caution as dense fog continues to affect visibility across parts of northern India.