Heavy rains drastically reduced the pollution level in the national capital, which recorded the best air quality of this year  today. According to the Central Pollution Control Board (CPCB) data, the overall air quality index  in the city was 133, which falls in the 'moderate' category.<br />''<br />''The CPCB data showed, this is the first time this year that an AQI as low as 133 was recorded. Delhi has been battling hazardous pollution level for the past few months and for the last one month the air quality has been oscillating between 'very poor' and 'severe' category.<br />'' <br />''<br />''An AQI between 100 and 200 comes under 'moderate' category, 201 and 300 is considered 'poor', 301 and 400 'very poor', while that between 401 and 500 is 'severe'.<br />''<br />