Uttar Pradesh is experiencing dense fog and a cold wave, with hazardous visibility conditions reported, especially in eastern districts. Temperatures in Lucknow are between 9-13°C, with highs of 19-25°C, and humidity at 70%. The air quality index has deteriorated to the 200-300 range, with PM2.5 and PM10 levels spiking due to fog. These conditions are expected to persist through January 3rd before gradually improving.