In Bangladesh, one of the most polluted cities in the world has done more than any other worldwide to rid itself of harmful PM10 particles
Once upon a time, the sweltering summer in Rajshahi was made worse by a familiar factor on the Asian subcontinent. Windows would have to be bolted shut, not because of the wind or monsoon, but because of the smog.
Dust drummed up from dry riverbeds, fields and roads, and choking smog from ranks of brick kilns on the edge of town helped to secure the place a spot in the top tier of the worlds most polluted cities.
Then suddenly Rajshahi, in Bangladesh, hit a turning point so dramatic that it earned a spot in the record books: last year, according to UN data, the town did more than any other worldwide to rid itself of air particles so harmful to human health.
We didnt know about this, admits Ashraful Haque, the citys chief engineer, who like some of his fellow residents is rather bemused by the achievement.
Rajshahi does not have a large industrial area, and it is too poor to have streets clogged with cars. Instead, Haque believes it was the campaign to clean up the brick kilns, as well as efforts to make the city greener, that have turned the tide.
Levels of larger PM10 particles went from 195 microgrammes per sq m in 2014, to just 63.9 in 2016, a reduction of about two-thirds, and the largest in the world in absolute terms. Smaller PM2.5 particles have been nearly halved to 37 microgrammes per sq m from 70.
Haque, who was born and educated in the city, remembers as a child having to close windows and doors to shut out a thin film of dirt that would settle across every surface in the house when a wind swept in from outside.
Nowadays its a different city, thanks to the campaign that began with a tree-planting drive over 15 years ago, and now encompasses everything from transport to rubbish collection. Dust still hangs heavy in the air on occasions, but the transformation has been welcomed by local residents in a country where urban authorities more often generate frustration and resentment.
Things have got better for my classmates with asthma, said Fatema Tuzzohra, a 13-year-old enjoying a riverside park after school. I love the city, it is really clean and green.
The city began tackling transport issues in 2004, importing a fleet of battery-powered rickshaws from China, and banning large trucks from the city centre in daytime. The three-wheelers are the main form of public transport, and their batteries keep the air free of the petrol fumes that hang over other cities.
Upgrades to the brick kilns, changing chimneys and fuel, have reduced the amount of pollution they spew out around the city, Haque says. And he has personally designed and overseen a project to make the city centre greener while reducing the amount of dust kicked up by people and vehicles.
We have a zero soil programme in the city, with lots of planting and green intervention. When it works, there should be no part of the road that will be dirt. It will be all grass, flower or pavement, says Haque.
He became convinced that the city needed more pavements, after trips to study urban planning abroad. At the time the tarmac surfacing of the city roads mostly ended in a dusty verge, sometimes with open drains, dangerous and unappealing for walking along, he said.
In 2010, after a visit to London, I started creating pavements. I couldnt believe it, everyone has to walk at least 2km a day (in London), but here people finish lunch and look for a rickshaw. Even in the good neighbourhoods, there are no pavements.
Apart from encouraging a healthier lifestyle, they are vital for controlling dust in the air, he says. If you have them no soil will fly during the summer seasons. So far they have built about 9 mines (15km), but soon hope to expand to 30, he said.
The road transformation will go beyond pedestrians this month, when city workers start building the citys and the countrys very first cycle lane.
Take up is likely to be slow in a city already sweltering in the summer heat, and where the only people on bikes are those too poor to afford other transport, Haque admits. But inspired by trips abroad, he hopes to sow the first seeds of change.
I went to the river Thames and saw people riding bikes, I got the idea from Japan and China as well. We dont have enough land for a separate lane in many places, but where we can we will separate with a border, making a pavement and a cycle lane beside it.
People are proud of their town, and have started looking after it more closely after the transformation, says restaurateur SM Shihab Uddin, who spent nearly a decade working in Cyprus before returning to open his own chain of eating spots for the growing middle class.
It has changed so much, he said. I came back in 2009, and I was worried that I would find it hard to live here after so much time abroad. But it it was already transformed.
Saad Hammadi contributed reporting
Indias cleanest city
The small city of Tezpur in east India has traditionally had little to brag about. The holy Brahmaputra river roars at its edges and the mighty Himalayan mountains adorn its skyline, but couched between these geographical marvels, Tezpur itself is little more than a layover stop for travellers in the state of Assam.
But while many of Indias industrial towns have reached peak pollution levels, Tezpurs air is getting cleaner. Since the last WHO air quality report in 2014, Tezpurs PM10 pollution, caused by dust particles, has reduced more than any other Indian city to close to 15% of the level it was.
Tezpurs PM10 levels now stand at 11mg/m3. According to WHO guidelines, the permissible limit for PM10s is 20mg/m3.
Tezpurs air quality improvement stands out in India, where focus on industrial development and rapid urbanisation in recent years has driven pollution levels up in most other cities. According to the WHO report six of the10 most polluted cities in the world are in India, putting millions of people at serious risk of cardiac and respiratory infections.
M Nath, senior environmental engineer at the Pollution Control board says that Tezpurs clean air is noticeable to travellers from other cities. When we have visitors from other cities like Delhi or Guwahati, they immediately feel the difference in the air quality here, Nath says. But were a small city, we dont have any major industries that cause a lot of pollution and people are conscious [about the environment]. It may not be so easy in other places.
It is difficult to single out any one reason for Tezpurs improvement , but Nath explains that there are many green activities going on in and around Tezpur. Heightened awareness about the environment means people are making conscious efforts to go green. People in Tezpur are very conscious about the environment, Nath says.
In recent years, rising incomes and greater awareness about the environment means people have started buying cars which meet the latest emission standards, and discarded older, polluting vehicles.
Last year, over 800 trees were planted by students in the city, as part of a massive environmental campaign at Tezpur University.
Activists such as Jadav Payeng, nicknamed Indias forest man, have also made significant efforts to improve the environment in regions near Tezpur. For the last 30 years, Payeng has planted an entire forests worth of trees, covering 550 hectares of land.
Industrial efforts to cut back on coal-powered machines have also helped significantly. The supply of liquefied petroleum gas (LPG) has improved a lot, and so many tea plantations are using it now, he says. LPG is produced from fossil fuels, but produces virtually no particulate pollution compared to burning coal.
In the Indian state of Assam hundreds of tea plantations produce millions of kilos of tea, which are exported around the world. Until recently, many of them depended solely on coal to fuel their machines.
Nath says LPG connections have now reached even more remote village areas near Tezpur. Access to LPG connections and subsidies from the government have prompted many villagers to use cleaner fuel for cooking and burning waste. People dont need to use wood fires any more, most of them have access to LPG.
Sanjiv Eastment a manager for McLeod Russell, the worlds biggest tea producer, says he can feel the improvement in air quality since the company started using LPG in their incinerators. Not just outside, you can feel it in the factory itself, he says. Theres no more dust, no more breathing problems.
Eastment estimates that better technology and more easily available LPG connections have saved thousands of tonnes of coal in recent years. We make around 100 million kilos of tea a year, and for each kilo of tea we burn around 1kg of coal. But it used to be much more 1.6, 1.8 kilos a few years ago. Now we have new boilers that are more energy efficient and our incinerators are fuelled by LPG, he says. We still need to use coal for our tea dryers though.
According to Eastment, the company switched from coal to LPG because it was cheaper. After all were in the business of tea to make money, he says.
Strong regulation and demands from foreign countries to meet production standards have also contributed to the change. Foreign countries have become less willing to accept tea imports unless they are certified by the Rainforest Alliance. It means that all open fires have stopped even in the workers quarters, to cook or burn waste, Eastment says. That makes a really big difference.
For Nath though, it is adopting the right attitude to the problem that is key. The Pollution Control Board has run campaigns in schools and villages to encourage people to adopt greener lifestyles. The Pollution Control Board has held several campaigns at schools and villages to encourage people to adopt greener lifestyles. People have been very enthusiastic, Nath says. They are really proud about the environment here We look after our city.