New Delhi, Oct. 14 -- Delhi's air quality slipped back into the "moderate" category on Tuesday, a day after rainfall brought brief relief and pushed the air quality index (AQI) into the satisfactory range for the first time this month, according to Central Pollution Control Board (CPCB) data. The city's 24-hour average AQI stood at 158 on Tuesday, compared with 83 on Monday and 111 on Sunday. Monday's improvement followed early morning showers that also brought down temperatures. CPCB defines an AQI between 0 and 50 as "good", 51 and 100 as "satisfactory", 101 and 200 as "moderate", 201 and 300 as "poor", 301 and 400 as "very poor", and 401 and 500 as "severe". Meanwhile, Delhi recorded a maximum temperature of 32.5degC on Tuesday, 0.7 degr...