Here's what an article about why Toronto is often referred to as "The Big Smoke" could look like:

Introduction

Toronto, the capital of Ontario and the largest city in Canada, has diverse and fascinating cultural roots. Besides being known for its multiculturalism, architectural ingenuity, and vibrant art scene, one particular quirk about Toronto piques the interest of many – its nickname, "The Big Smoke". This nickname is not exclusive to Toronto and has been used to describe several other cities, including London and Sydney. However, its application to Toronto carries unique historical and environmental implications.

A Tale of Industry

One possible reason might be the city's industrial past. Like many growing cities in the 19th and 20th centuries, Toronto rapidly industrialized. Factories sprung up, producing goods and burning coal, contributing to the city's "smoky" nickname. This rapid industrial growth was often accompanied by environmental degradation, including air pollution - which could have led to the city's smoky moniker.

A Metaphor for Growth

Another explanation for why Toronto is called 'The Big Smoke' could be metaphorical. The term 'Big Smoke' often refers to a place that is seen as a significant hub of activity, a city that offers better prospects than smaller towns or rural areas. As Toronto grew rapidly into a prosperous metropolitan city, individuals from across the country and around the world began to flock here, seeking more promising opportunities - hence heading towards 'The Big Smoke.'

Urban Life and Air Quality

While these nicknames may paint a charmingly historic picture of Toronto, they also bring to light an essential environmental concern plaguing cities worldwide - air quality. As an ever-manifesting feature of urban life, the "smoke" continuously hangs over the city, which is a potent symbology of persisting air quality challenges. Toronto has significantly advanced over the years, replacing its factories with high skyscrapers and office buildings, but issues related to air quality remain.

Environmental Policies and Air Quality Improvement

Toronto has made great strides in improving its air quality as the city recognized its responsibility to protect public health and the environment. The government has implemented policies that limit emissions of industrial pollutants that produced much of the "big smoke." Additionally, the introduction of smog control initiatives and changes to public transportation have significantly contributed to improving Toronto's air quality.

Conclusion

While Toronto's nickname "The Big Smoke" can be associated with an era of rapid industrial growth and pollution, the city today is known for its rich diversity, pioneering technology, and an abundance of opportunities. Toronto has learned from its history and has instituted policies, programs, and attitudes that aggressively tackle pollution and air quality. Finally, with "The Big Smoke" as a moniker – Toronto will always be reminded of its past, shaping its future, ensuring a greener, cleaner space for its residents and the generations to come.