Eight of us have been cycling through dense smog since Ningbo, unaware that we are peddling through historically abysmal pollution.

Just before we reach Lake Taihu, on the Yangtse River Plain, south of Shanghai, Ride For Hope organiser Nicholas Smith calls together the riders for a roadside meeting. “I’ve just received word from Shanghai – I’m afraid we won’t be able to cycle into the city tomorrow,” he tells us, his face grave. “The pollution is too serious.”

According to the Shanghai Daily, “The city’s PM2.5 density soared to 468 micrograms per cubic metre by midnight, more than six times the nation’s limit of 75.”

“We’ll have to reconvene in a month or two to finish this leg of the journey,” says Smith.

We’ve made it across four provinces and already ridden more than 2,000 kilometres. Now it looks as though our grand finale, a triumphant ride into Shanghai, will have to wait. There is no disguising the despondency of the team as we proceed into a mist-enshrouded Suzhou.

The Ride for Hope cycle tour began in Shenzhen on November 16 and was meant to link the mainland’s original free-trade zone to its newest.

It was organised by Smith, resident manager of the Futian Shangri-La hotel, to raise funds for the construction of water cellars for a remote Yao-minority village in the Guangxi Zhuang autonomous region.

The team – who have, over the course of three weeks, been in the saddle for eight to 14 hours a day, loosely following G, or secondary, roads – includes Li Xiaobao, 27, a Hubei province native who now resides in Nanning (in Guangxi Zhuang), where he operates a successful food-processing business. He is sharp, and doesn’t suffer fools gladly. Also from Nanning are 27-year-old Lu Baokang (who we call Big Lu) and 21-year-old Lu Yushui (Small Lu). Both are crazy about bikes and their athleticism has been crucial in the mountain stages of the journey as they have hung back to assist anyone trailing – usually me. Shenzhen native Carl Wu Zhifeng has been Ride For Hope’s mechanic. Stoic and unwavering, he has been on hand whenever punctures or malfunctions have hindered our progress north. Smith, 38, a two-metre-tall tank of a man, has led from the very beginning. Ex-military, the Welshman’s navigational skills and, occasionally, his first-aid training have helped us through some difficult situations. Hongkonger Herman Wong Yat-ming completes the team. At 52, he is the oldest participant, but in excellent physical shape.

He speaks English, which has been invaluable in helping Smith communicate with the team.

We hardly knew each other when we set out, following a starting ceremony in Shenzhen, but over the weeks we have bonded like men at war while negotiating the obstacles that litter the mainland’s frenetic roads.

“I FEEL LIKE I’M WEARING Dongguan on my face,” Smith says on the second day of cycling. “I had no idea there was so much construction.”

Navigating the Pearl River Delta is hardly the best way to ease into our journey. This is the manufacturing centre of the world and – beyond the ostentatious downtown areas – the delta is essentially a sea of factories connected by bumpy roads upon which overloaded trucks spill debris as they hurtle along. There’s very little countryside. Shenzhen, Guangzhou and Dongguan converge as one great, chaotic megacity and crisscrossing it is enough to drive any reasonable man insane. Everything appears hurried, temporary and unsound. “China’s ambitions are boundless, the execution abysmal,” I tell my diary.

We finally find open country after passing Huizhou, a small city bisected by the East River on the fringes of the delta. We are only seven at this point and our small fleet pedal in unison down empty roads, enjoying views dominated by rice paddies and water buffalo.

Nevertheless, man’s impact is never far away in such a populated country and even while cycling the rural back roads, one passes quarries, swathes of deforested hillsides and the occasional building site.

“I don’t think we’ve gone 10 kilometres without seeing some kind of construction work,” says Smith, as we peddle towards the quaint river town of Huidong, where bicycles and scooters still outnumber cars.

Only in the most mountainous regions will we witness China untamed.

We encounter our first mountain range later that day as we cycle through the Hakka uplands – the craggy areas of Guangdong province occupied by a Han sub-group that arrived in the south long after the Cantonese. The traditional way of life of the Hakka persists only in these isolated valleys. Our thighs burn as we crawl up unforgiving slopes but the stunning scenery, dotted with sequestered farmhouses, gives rise to the sensation that we are somehow travelling back through time, towards a less contaminated age.

Our final stop in Guangdong is harrowing. The road we enter the city of Jieyang on has been widened at the expense of the front halves of several houses. Still inhabited, these homes let it all hang out. Bathrooms and shower-heads are visible; wooden bedroom doors open straight onto the street; furniture has been left balancing on lips of concrete – balconies that were once part of whole rooms. As we peddle on, we ride alongside rivers coated in algae born from the overuse of chemical fertilisers.

The traffic is an abomination, as the new BMW class wrestles for space with the toiling masses still getting by on rickshaws, motorbikes and smog-bellowing trucks. A restaurateur has caged a live deer outside his eatery and goats are being milked in the middle of busy turnpikes.

Small Lu makes the decision to purchase a beautiful river bird from a restaurant and sets it free in a rural area between Chaozhou and the provincial border.

We enter Fujian province with a sense of relief. There is a salty sea breeze, the mountains are forested and the rivers flow with clear water. People wear bamboo hats and inhabit towns that are distinctly middle class. The area elicits what Smith calls “the China of the imagination”.

The most sensational day of cycling comes on the 150- kilometre leg between Yunxiao county and Xiamen, when Smith leads us off the main road and through a series of villages set against towering mountain vistas. A temple set before a stream calls to mind scenes from mountainwater ink paintings.

Southern Fujian may well be all that is left of old China; as we push north we cycle past Qing villages, ancient Taoist shrines, Buddhist temples and ancestral burial grounds. But much of this heritage is marked for demolition. As the Communist Party seeks to turn this agrarian land into an urban nation, it is not only the natural environment that is taking a hammering: history, too, is succumbing to the endless drive towards modernity.

Xiamen presents us with a clear example of just how absolutely this country is being remodelled. In this special economic zone, vast areas have been demolished to make way for malls and high-rise residential housing. There is little left to recall historic Amoy, as early European traders knew this thriving port.

The 260 kilometre-long coastal conurbation of Xiamen and Fuzhou, though not as polluted or anarchic as the Top: Ride for Hope cyclists head for the mountains.

Above: Singaporean Xin Xin is assisted by Smith after falling from her bike on the road to Hangzhou.

Pearl River Delta, presents us with a few more days of tough urban cycling. Beyond Ningde, in northern Fujian, however, we get back onto rural roads. The cacophony of car horns is replaced by the sound of the wind as we ride past farmers harvesting orange groves and crisscross the many waterways on scenic stone bridges.

On day 14 of Ride For Hope we make our toughest ascent – a gruelling 1,320 metres through bamboo forests.

“Keep going!” Li yells as I groan my way up the slope.

The climb is arduous but the scenery is spectacular as we ascend through the tea fields for which Fujian is renowned.

When night falls, however, the scene turns from picturesque to perilous.

As the prospect of pedalling off a cliff plays on my mind, it is the crashing temperature that most hinders our progress. We finally arrive in remote Zherong at about 8pm, with the mercury at zero; just a few days earlier we were lathering ourselves in suncream. Zherong is a small, well-mannered town and, as we leave early the next morning, one coated in frost.

In Wenzhou, a Zhejiang city whose skyline is dotted with the red crosses of Christian churches, we are joined by our “auspicious” eighth rider, a triathlete from Singapore named Xin Xin. She is a veracious team player whom the boys warm to immediately. She will have to become road-hardened quickly, but none of us are fully prepared for what we are about to encounter crossing Zhejiang. The first thing that becomes apparent is how aggressive the drivers are here.

“They’re known to be assertive in business,” Smith says, as we cross the brown expanse of the Ou River on a heavy, metal barge straining with cyclists and pedestrians impatient to alight on the mountainous side of town. “I think this is reflected in their driving etiquette.”

For a government whose main aim – as confirmed at The Third Plenary Session of the 18th Central Committee of the Communist Party – is to “boost economic development”, car ownership is a key driver. “Car sales remain in fast lane,” China Daily reports. “Double-digit increase seen for 2013 …” The world’s most populous country, once equated with the bicycle, is fast becoming the world’s largest traffic jam. As we peddle into horrendous smog, I wonder how the Party plans to realise its “strong commitment to environmental sustainability”, as proclaimed in the same edition of the newspaper.

We are back to wrestling for space with uncivil drivers in the same kind of industrial landscape we saw in the Pearl River Delta. Only day 18 yields any worthwhile Zhejiang scenery. Autumn has settled along the 200- kilometre, 14-hour expanse between the cities of Taizhou and Ningbo, turning the leaves myriad shades of crimson and amber.

Here, the bathroom-tile housing of the south has given way to more scenic brick farmhouses. From fences hang strings of rice noodles that look like sheets of white cotton blowing in the breeze.

Exhaustion begins to take its toll in Zhejiang. Both Wong and Small Lu fall off their bikes, but it is Xin Xin’s tumble that proves most serious. She fractures her arm on the road to Hangzhou and though she will heroically complete the day’s segment, doctor’s orders prevent her from cycling on to Suzhou.

“The devil on my shoulder is saying get a first-class ticket to Hangzhou,” says Smith, parked up next to a highspeed- rail station. He later expounds, “China is so forward in some ways, so misguided in others. They have the most amazing train system and 50 metres away they’re burning trash. There’s no middle ground; it’s one extreme or the other. Everyone’s just pushing, pushing on ahead.”

THERE IS A GREAT SENSE of injustice at the prospect of being prevented from completing Ride For Hope.

All along the way we’ve negotiated environmental travesties but now it looks as though the smog has brought down the curtain on our adventure. Cycling into Shanghai as a group required permission from the local government; the Party is sensitive about privately organised group activities. We were given authorisation but now the health department is leaning on the event organisers.

A smoggy finale could prove a PR catastrophe for the city and for Shangri-La hotels. Nevertheless, after some latenight negotiations, Smith announces the powers-that-be will, after all, let us cycle into Shanghai.

“They’ve agreed, as long as we wear masks,” he says.

It appears our tenacity has won us favour with the gods. Just outside Shanghai, the air clears somewhat.

Xin Xin joins us in Pudong as we cycle towards the Kerry Hotel. It is an emotional experience as we take our last turn together towards the finish and are showered in champagne and flash photography. Having cycled for three weeks and raised 400,000 yuan (HK$507,000) for charity, our modest team basks in the adulation.

As the fanfare dies down, I recall a propaganda poster we saw on a bridge somewhere between Xiamen and Fuzhou. It read simply, “Eat Great Bitterness.” For three weeks we have witnessed people enduring calamitous pollution, dreadful traffic, relentless construction, poverty born of rural isolation and – in the big cities – the emergence of slums, hitherto almost unheard of in China.

Our endurance ride is now at an end but many of the people who live along the roads we’ve travelled will be eating great bitterness for years to come.

Shangri-La Hotels and Resorts is owned by the Kerry Group, the biggest shareholder of the SCMP Group, publisher of the South China Morning Post. Thomas Bird is the author of a new book, Hong Kong’s Back Yard: A Guide to the Pearl River Delta.