Fireworks activity causes short-term air pollution. The festival of Diwali is celebrated with firecrackers in India during October/November every year. The ambient air quality was assessed in Vadodara city, Gujarat state of India during Diwali festival for the consecutive years 2009, 2010, and 2011. During the festival day, the average concentration of PM10 was increased 35 times compared with a normal day before Diwali. Similarly, concentration of SO2 has increased 23 times and NOx has increased 3 times on the festival day. The diurnal pattern of the above pollutants showed an increase in the night. Air quality index calculated for 24 h average during Diwali 2009 in two stations exceeded a value of 125 indicating severe air pollution in Vadodara city. It is also confirmed that the yearly pollution load is getting increased in Vadodara city as the air quality index value has a gradual increase from 2009 to 2011. The good correlation coefficient between different pollutants confirmed the firework as the prime source of pollution. Based on PM10 concentration, the highest mortality rate was found to be 30.4 %. The short-term high accumulation of PM10 is a matter of serious concern for city dwellers as it can penetrate deep into the lungs and cause many respiratory and cardiovascular diseases.