Air Pollution Analysis Jan- March 2021

  • For the sake of comparison two periods are compared above i.e. April 2019 to March 2020 and April 2020 to March 2021.
  • The first two quarters from Apr 20 to Sep 20 show a much better air quality scenario when the nation wide lockdown was in works. During the same period, in the previous year showed AQI surpassing 100 in most of the cities.
  • While the AQI started deteriorating from September 2019 onwards in the 2019-20 period, it was only in November 2020 that the AQI started deteriorating due to onset of winters as well as restarting of the economic activities.
  • The first quarter of 2021 show similar trends in both the years with AQI transitioning to better category in March.
  • Jharsuguda and Asansol improved in the first quarter and the transition can be seen in the tables below. Alternatively, Delhi and UP showed better AQI for the first quarter of 2019.

Table 1 – More greener phase during full and partial lockdown in 2020

 Cities Apr-20 May-20 Jun-20 Jul-20 Aug-20 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21
UP 105 88 66 74 57 125 164 295 320 327 230 107
Raigarh 94 82 73 50 60 49 0 80 87 87 0 0
New Delhi 104 77 79 64 52 83 158 326 298 296 243 149
Korba 114 103 89 86 68 89 157 183 182 187 162 189
Kolkata 44 30 35 33 32 38 66 120 236 215 157 97
Jharsuguda 95 59 52 58 58 75 107 181 238 260 169 155
Asansol 144 122 128 97 99 146 204 273 357 340 296 232
Sambhalpur 96 70 62 64 64 70 111 186 240 172 181 197
Raipur 72 81 63 58 96 98 130 251 192 0 0 0

 

Cities Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-19 Jan-20 Feb-20 Mar-20
UP 152 272 334 120 112 93 260 291 306 187 129 0
Raigarh 0 0 121 149 132 82 123 194 166 142 127 90
New Delhi 110 100 99 100 110 140 215 305 280 251 185 108
Korba 157 132 139 115 144 124 199 234 200 179 197 138
Kolkata 63 102 109 69 61 47 136 196 206 211 168 86
Jharsuguda 0 0 207 107 133 99 189 270 238 246 232 289
Asansol 188 210 210 191 158 133 305 391 368 376 356 250
Sambhalpur 125 109 202 169 211 179 322 371 275 187 152 101
Raipur 80 80 82 75 87 63 195 272 203 170 149 103

 

  • Kolkata pulled back to Good AQI category for six months straight from April 2020 – the trend not witnessed in 2019.
  • From the data it can be interpreted that Asansol remained in the very poor category in 2019 for five straight months from October2019 to February 2019 whereas only two poor category months are seen for 2020-2021.
Jan-19 Jan-20 Jan-21 Feb-19 Feb-20 Feb-21 Mar-19 Mar-20 Mar-21
UP 311 187 327 311 129 230 198 – 107
Raigarh – 142 87 – 127 – – 90 –
New Delhi 208 251 296 208 185 243 130 108 149
Korba 195 179 187 195 197 162 155 138 189
Kolkata 156 211 215 156 168 157 102 86 97
Jharsuguda – 246 260 – 232 169 – 289 155
Asansol 259 376 340 263 356 296 268 250 232
Angul 117 190 – 132 – – 110 – –
Sambhalpur 146 187 172 146 152 181 131 101 197
Rourkela 124 82 – 124 120 – 124 85 –

 

  • Looking at the table above, it is clear that transition in AQI categories is taking place in the same period over different years.
  • Even if there is no AQI category transition (i.e. from good to poor or from poor to good) there are intra variations in the AQI range which indicates milder or increased activities. This goes on to indicate that air quality is dynamic and a pollution source which may be a point source or a line source will impact areas even far away from the source as the pollutants mix with ambient air and disperse as per the prevailing weather conditions.
0-50 51-100 101-200 201-300 301-400 >401 Not Work
New Delhi Jan 0 0 2 18 8 3 0 31
Feb 0 0 10 12 5 1 0 28
Mar 0 1 27 3 0 0 0 31
Korba Jan 0 2 17 11 1 0 0 31
Feb 0 1 24 0 0 0 3 28
Mar 0 0 23 7 0 0 1 31
Kolkata Jan 0 0 12 19 0 0 0 31
Feb 0 3 18 7 0 0 0 28
Mar 0 15 15 0 0 0 1 31
Jharsuguda Jan 0 0 4 8 4 0 15 31
Feb 0 1 17 10 0 0 0 28
Mar 0 4 23 2 2 0 0 31
Asansol Jan 0 0 0 6 22 3 0 31
Feb 0 0 1 9 18 0 0 28
Mar 0 0 6 17 2 0 6 31
Raigarh Jan 0 20 7 0 0 0 4 31
Feb 6 8 2 0 0 0 12 28
Mar 4 1 0 0 0 0 26 31
Sambhalpur Jan 0 0 5 9 3 0 14 31
Feb 0 14 11 1 0 0 2 28
Mar 4 0 0 0 0 0 0 4
70 224 139 65 7

 

  • Very few locations in the Good to Satisfactory category except Kolkata in March, Sambalpur and Raigarh too showed satisfactory AQI.
  • Only in March Delhi improved to Moderately polluted category. Asansol is the only location where AQI for most of the months of January and February remained in very poor category.
  • Delhi and Asansol each had 3 days of severe AQI in the month of January. Maximum concentration of AQI across all locations was in the poor category.

  • AQI remained above 200 at Transport Nagar, Gandhi Nagar and Petrol Pump.
  • No where the AOI is even in the satisfactory category except Urja Nagar, Shanti Naga, Sai Temple and RP Nagar for the month of February.
  • AQI rose to moderately polluted to poor across January through March 2021.
  • Worst AQI of 321 was noticed in Dipka mines for the month of January with the minimal reaching 206 in the month of February.