Lahore's smog: lessons to be learnt | The Express Tribune

In December 1952, dense smog covered Greater London and Londoners choked in a stew of polluted air, leading to over 4,000 deaths in two weeks.

Below freezing temperatures, a high-pressure system and a complete absence of wind produced unique temperature inversions in the Thames Valley, with a layer of warm air covering the cold air at the ground level. It effectively trapped smoke particles generated by the burning of fuel and the smog became widespread.

The London government soon learnt the root cause of smog and noted that the domestic coal-based fire is the biggest smoke producer. As a ratio of the coal burnt, it produces twice as much smoke as the industry.

The government then passed The Clean Air Act 1956 that introduced the term "smokeless zones" and within a smoke-controlled area, it was an offence to emit smoke from homes. This and many other drastic measures helped London avoid smog in the next 70 years.

Drawing parallels in 2024, smog is now in the fifth season for most of Pakistan. For some reasons, the government has not yet located the root cause and often cites a myriad of factors coming into play such as emissions from transport and industrial sectors, while the trigger point apparently lies with the crop and trash burning practices in winters.

The tight schedule of harvest-to-sowing transition in the rice-wheat rotation cropping system is the main reason why farmers opt to burn their crop residue. It is well-known that the residue of rice and wheat crops can't be used as animal fodder or as biofuel and it remains a nuisance for farmers to clean up.

The pre-monsoon residue burning contributes to smog, but high temperatures help to keep it at bearable levels. However, the burning of post-monsoon residue in November amplifies the effect due to cold weather.

So, the first burning question for policymakers is: can governments enforce a ban on burning the crop residue? Apparently, no, due to political reasons and difficulty in enforcement, but the government can at least discourage crop residue burning.

For example, it can offer interest-free access to credit or a cash prize for green practices to farmers who don't resort to these stubble burning practices. Verification of this can be done using GIS data received from satellites for months of October and November.

However, this policy alone won't help much. During Covid times (November 2020), when schools and offices were closed and there was no pressure of traffic in early morning hours as well as no noticeable construction activity, we noted that the smog was quite manageable despite the prevalent stubble burning practices. This means that crop burning alone is not the culprit here.

In fact, for months of November and December, the government's goal should be to ensure zero transport activity in early morning hours and in evenings, especially after sunset. This means that offices should open at 10am and close at 4pm, and remote work should be encouraged.

Similarly, academic institutions, if must be opened, should have a four-hour shift – probably from 11am to 3pm. Markets and all commercial activities should come to a halt after evening hours and a lockdown should be in effect.

Construction activity in winter should be banned (with some exceptions) and industrial zones should be gradually moved away from residential zones. There should be regulations to stop any residential schemes or settlements within 30 km radius of industrial zones.

Lastly, solid fuel – wood and coal – burning for heating is also a leading factor for systemic smog in rural Punjab. We saw how London benefitted from total phasing out of solid fuels for households.

Poland's city Rybnik used to face smog for four months till they rolled out a clean fuel policy for households that helped them replace old stoves with modern heating installations running on renewable energy sources.

Financial subsidies to help residents afford the transition to cleaner heating and cooking were also offered, while strict controls and inspections by authorities were done to ensure compliance.

This helped the Polish city reduce its smog days to a mere half a month in 2024 from four months in 2014. This is the kind of transformation we need in Pakistan to evade the climate apocalypse at hand.

The writer is a Cambridge graduate and is working as a strategy consultant