However, the highway has attracted criticism for its environmental impacts, including concerns about its footprint on designated farmland in the Greenbelt, and its implications to encourage urban sprawl and induced demand.

Following the 2018 Ontario general election in June of that year, the new Progressive Conservative government of Doug Ford announced the resumption of the suspended EA in November.

[12] The report identified the need for a controlled-access highway as part of the city's ultimate transportation plan to serve western Brampton.

[13] In 2005, the Government of Ontario passed the Places to Grow Act, which set forth consistent urban planning principles across the province for the following 25 years.

The Growth Plan for the Greater Golden Horseshoe was released in June of the following year as a framework for implementing the act,[14] with a future transportation corridor identified north of Highway 401 between Guelph and Vaughan.

[15] Following the submission of a Terms of Reference on June 15, 2007, an EA began[note 1] on March 4, 2008, to establish conceptual routes for additional transportation infrastructure to interconnect the GTA West economic centres (Milton, Brampton and Vaughan) with Guelph and Waterloo Region.

[note 2] Simultaneously, the City of Brampton appealed an amendment of the Halton Region Official Plan to the Ontario Municipal Board.

[26][27] Stage 2 of the GTA West EA began in February 2014, intended to further refine the study corridor to a preliminary design.

[28] However, by this point public opposition to the corridor began to appear, with the group Environmental Defence starting a campaign against the proposed highway by 2015.

[30] A three-member advisory panel[note 3] was formed in October 2016 to assess alternative approaches to meet projected traffic levels.

[34] The advisory panel report was released on May 29, 2017,[35] recommending that the EA be stopped, and the "development of a single transportation plan for the Greater Golden Horseshoe" proceed in its place.

[42] As part of the PCs Fall Economic Statement, released in November 2018, the government committed to the campaign pledge of resuming the suspended EA for the GTA West Corridor, "in order to speed up travel and alleviate traffic congestion".

[43][44] In September and October of that year, a series of Public Information Centres were held in which the preferred route and interchange locations were announced.

[53][54][55] In response, provincial Minister of Transportation Caroline Mulroney stated that she would work with the federal government to address “newly found concerns" on potential adverse effects on species at risk.

[61] Following this, Attorney General of Ontario Doug Downey announced that the province would seek legal action to prevent the federal government intervening in Highway 413.

[64][65] Following the announcement, provincial Minister of Transportation Prabmeet Sarkaria stated "we finally have certainty to move forward with the ...

In addition to increasing air pollution and greenhouse gas emissions, opponents claim the highway would disrupt woodlands, waterways, wetlands, wildlife habitats and species at risk.

[73] According to the Toronto and Region Conservation Authority, the highway would specifically impact 85 waterways, 220 wetlands, 10 different species at risk and hundreds of acres of vulnerable wildlife habitat.

[76] Consequently, they claim it would increase car dependency in surrounding areas and ultimately only save commuters around 30 to 60 seconds of travel time.

[73] Avison Young, a real estate services firm, estimated around 62,000 acres (250 km2) of developable land is available located within 2 kilometres (1.2 mi) of the 16 proposed interchanges.

[78] In 2021, a Toronto Star investigation noted that 3,300 acres (13 km2) of land along the route was owned by 8 major property developers, several of which had donated to Doug Ford's Progressive Conservative government.

[97] The Toronto Metropolitan University Centre for Urban Research and Land Development (CUR) also specifically supported the streamlining of the EA process, noting that “It is simply taking too long to bring critical infrastructure improvements such as roads, transit, sewers and water to completion".