An Inspired Indication to Air Pollution Mitigation

The Air Quality (AQI) and pollutant load in terms of PM_2.5 and PM₁₀ were analysed to determine the impact of human activities on the ambient air quality of Kolkata during the festival of Durga Puja 2023. Data sets obtained from the online monitoring stations installed in the city through public domains of West Bengal Pollution Control Board ( WBPCB) reveal how

• Traffic regulations in the city and reduce in vehicle emissions
• Rain and weather change

drastically reduced the ambient PM concentrations and improved the Air Quality for the main four days of the festival. But it is noticed immediately after the festivities the air quality has returned to it levels almost immediately.

The WBPCB stations at Avidipta Housing Complex, Santoshpur, Urbana Housing Complex, East Kolkata Township and Flora Fountain, Tangra were considered for the analysis.

Figure 1. Daily Mean AQI, PM2.5 and PM10 in Kolkata Pre, During and Post Durga Puja,2023

Specific traffic regulations imposed in the city from 17^th October to 24^th October 2023, not only relieved pandal hoppers and daily commuters to visit pandals as well as maintain emergency services, but also brought down the air pollution levels. The Mean daily AQI dropped steadily from 122.75 on 18^th October (Moderate Category) to 74.41 (Satisfactory Category) on 23^rd October on the eve of Navami and reached 44.39 (Good Category) on 24^th October on the eve of Maha Dashami.  While PM₁₀ had been slightly above the 60 ug/m³ permissible limit by CPCB, the PM_2.5 concentration was marginally below the prescribed 40 ug/m³ limit. Both saw a drastic drop on Maha Dashami 24th October 2023.

The post Durga Puja air quality drastically deteriorated following the removal of the traffic regulations and the AQI spiked back to the Moderate Category at 102.51 by 27th October 2023.

Several causes for the drop can be estimated and include:

Vehicular Emission Factor:

• Vehicle Bans on roads near pandals significantly reduced localised emissions as people chose to walk the distance.
• According to Traffic Notification (TP/29) dated 10.10 2023 by Kolkata Police, prohibition on all types of goods vehicles within the city roads between 8 a.m. and 4 a.m. (except emergency services) was imposed from 17th October to 24th October.
• As per the same Traffic Notification, all vehicular traffic was banned between 17th to 24th October along 107 major roads covering North, South, South West, Central, South East and South Suburban parts of the city.
• Stringent curbs and restrictions on parking, taxi and auto movement and private transport vehicles near zones with big puja pandals were imposed. As per the Traffic Notification, 125 no-parking zones near major arterial roads throughout the city were established that included no passenger dropping/pickup and suspension of earmarked taxi stands. These possibly reduced idling emissions from traffic congestions around these heavy traffic zones.
• As per a report by The Telegraph dated 17.10.2023, dynamic traffic re-routing was practiced to minimize the occurrence of jams and facilitate pandal hoppers to explore major parts of the city on foot, limiting the use of private cabs and taxis, reducing emissions
• As per a report in the Financial Express dated 20th October Mondal, A. (2023, October 20) , a highly versatile and efficient Metro Service plan for pandal hoppers and commuters was declared by Mr. Kausik Mitra, Chief Public Relations Officer (CPRO), Kolkata Metro. The train schedule ensured availability of metro at 5-6 min intervals in the North-South corridor covering night-long hours from 12 pm to 6:30 am on all days starting from 20^th The efficient metro service and timings significantly reduced dependency on cars and busses which might have contributed to the reduction in pollution levels.

Weather Factor:

• The city saw moderate showers throughout Navami and Dashami and the precipitation greatly helped reduce the ambient PM concentrations for the last two days of Durga Puja. This light rain was a result of depression formed over west-central Bay of Bengal. Parts of Kolkata experienced storm-like situation and light rain, whereas the entire city was mostly overcast on 24th October (Dashami).
• The presence of low-pressure systems and the rainfall, particularly during the last day of Durga Puja, contributed to a reduction in air pollution within the city. This favourable weather condition alleviated the usual pollution concerns associated with the festive season.

Conclusion

In conclusion, the city experienced a notable reduction in air pollution during Durga Puja, primarily due to well-executed measures, including an efficient Metro Service and traffic management. The presence of low-pressure systems and rainfall, especially on the last two days of the festival, further alleviated pollution concerns. These findings underscore the effectiveness of daily strategies such as good traffic management, promoting public transport as preferred modes of intra-city commuting in rapidly improving air quality.

Annexure:

Station 1: Avidipta Housing Complex (Nitai Nagar, Santoshpur, Kolkata, West Bengal 700075) (22.494470945618282, 88.39991916908221)

https://www.google.com/maps/place/Avidipta+Housing+Complex,+Nitai+Nagar,+Santoshpur,+Kolkata,+West+Bengal+700075/@22.4937401,88.3932846,14.75z/data=!4m6!3m5!1s0x3a02715fd491a031:0xea012dee9e01fb12!8m2!3d22.4931439!4d88.4000884!16s%2Fg%2F11qs979kmd?entry=ttu

Station 2: Urbana Housing Complex (783, Anandapur High Rd, Madurdaha, East Kolkata Twp, Kolkata, West Bengal 700107) (22.5113850  88.4123840)

https://www.google.com/maps/place/Urbana+Kolkata/@22.511633,88.4132092,15z/data=!4m6!3m5!1s0x3a0273fa03e4e149:0xb6345f21c9860389!8m2!3d22.511633!4d88.4132092!16s%2Fg%2F12q4wvp16?entry=ttu

Station 3: Flora Fountain (45, Christopher Rd, Seal Lane, Tangra, Kolkata, West Bengal 700046) (22.5486280 88.3822560) 

https://www.google.com/maps/place/Flora+Fountain/@22.5483939,88.3768888,16z/data=!4m10!1m2!2m1!1sFlora+Fountain!3m6!1s0x3a02769330b5c123:0xa646512d64006b0b!8m2!3d22.5483933!4d88.3827158!15sCg5GbG9yYSBGb3VudGFpbloQIg5mbG9yYSBmb3VudGFpbpIBE2NvbmRvbWluaXVtX2NvbXBsZXiaASNDaFpEU1VoTk1HOW5TMFZKUTBGblNVUm9hMDlYVmxGQkVBReABAA!16s%2Fg%2F11cn065_99?entry=ttu

References:

Alexander, J. (n.d.). Traffic guidelines, maps and helplines for pandal-hoppers this Durga Puja. https://www.telegraphindia.com/my-kolkata/durga-puja-special/traffic-guidelines-maps-and-helplines-for-pandal-hoppers-this-durga-puja/cid/1974016

Mondal, A. (2023, October 20). Durga Puja 2023: Kolkata Metro offers night-long services on the North-South corridor – Check timings and more. Financial Express. https://www.financialexpress.com/business/infrastructure-durga-puja-2023-kolkata-metro-offers-night-long-services-on-the-north-south-corridor-check-timings-and-more-3277335/

Traffic Notification-Durga Puja 2023. (2023). In https://kolkatatrafficpolice.net/