The federal government has announced a conditional approval of the Northern Gateway pipeline, which would link the Alberta oilsands to a port on the B.C. coast.

Here's a brief primer on what you need to know about the pipeline.

What: The Northern Gateway pipeline is a proposed 1,200 kilometre twin pipeline that would carry bitumen from the oilsands in Alberta to Kitimat, B.C. From there, the crude would be shipped to Asian markets.

The $7-billion pipeline would be developed by Enbridge Inc., a major Canadian energy delivery company based in Calgary. Enbridge submitted its application for the pipeline to the National Energy Board in 2010. Since then, a review panel hosted consultations and heard from residents of the affected communities. The panel eventually approved the project in 2013, but with 209 conditions.

Controversy: The pipeline has been the source of much controversy, as supporters and opponents have advocated for and against the project going ahead.

Supporters say the pipeline would be a boost to the Canadian economy, worth an estimated $300 billion to Canada’s gross domestic product over 30 years. The pipeline would also create new job and training opportunities.

But the project has a long list of opponents, including environmental groups, residents groups, and several First Nations. They say the project threatens sensitive areas of B.C.'s coastline and the Great Bear Rainforest. Several aboriginal groups have threatened to challenge the project in court if the federal government approves it.

What one supporter says: Stockwell Day, a former Conservative cabinet minister, recently signed an open letter in support of the pipeline. He said that the proposal has gone through one of the "most rigorous" environmental assessments of any project like it, and will be sensitive to both local communities and environmental concerns.

"I think I'm like most Canadians. I want to see a strong and prosperous economy, but I don't want to see it at the expense of the environment," he told CTV's Canada AM on Tuesday.

"If projects like this don't go ahead… we're going to continue to lose opportunities for kids, for my kids, for my grandkids in terms of their own future."

Day added that there are already thousands of pipelines running across North America, and the Northern Gateway pipeline, if approved, will be one of the "safest and most sophisticated." He said additional safeguards have been put into the proposal as a result of community consultations, and added that several First Nations in Alberta have signed equity agreements, signalling their approval.

"There are risks with anything," Day said, giving the example of wind farms and the risks they pose to bird populations. "But we don't stop pursuing the possibility of wind energy."

What one opponent says: David Miller, the former mayor of Toronto and current CEO of the World Wildlife Fund of Canada, said the pipeline comes with too much risk, particularly because it runs through one of the "most important" natural regions of the world, the Great Bear Rainforest.

"There is no adequate way in the world to clean up oil spills of diluted bitumen, the kind that will flow through this pipeline," he said. "So if there are breaches in the pipeline itself that go into the salmon-filled waters and pristine rivers, there's a huge economic and environmental impact."

He noted that the region in B.C. where the pipeline would cross through already supports a thriving economy related to forestry, fishing.

"There are jobs that are working in harmony with the environment, fishing, limited forestry and we're risking trading those for jobs that are not working in harmony with the environment," he said.

Miller also said the coastal First Nations which are most likely to be impacted by the pipeline are strongly opposed to the project. The residents of Kitimat and across B.C. have also rejected the pipeline, he said.

"This project is in a place that's so pristine, we shouldn't be taking the risk, particularly against the will of the local people," he said. "British Columbians do not want a ‘Yes’ decision."

Politics: The pipeline has also been politically divisive, drawing support and opposition from different parties at both the provincial and federal level.

At the federal level, Conservatives support the pipeline, while the Liberals and NDP have called on them to reject the project.

B.C. Premier Christy Clark said the pipeline has not met five specific conditions that the province had initially set before it would grant its approval. The conditions include environmental protections, consultations with First Nations, and a condition that the province gets a "fair share" of the benefits stemming from the pipeline.

Shovels in the ground: Even if the pipeline is approved, the project will still face significant hurdles before construction can begin. In addition to the threat of legal challenges from First Nations communities, Clark said the pipeline will still have to get about 60 permits from British Columbia before construction can proceed.

As well, a coalition of groups in B.C. said they would organize a provincial citizens' initiative if the province eventually issues those permits. A similar initiative launched in 2011 forced the province to revoke the harmonized sales tax.

A successful petition from B.C. residents would force the provincial government to respond with one of two options: a vote in the legislature or non-binding provincewide vote.

With files from The Canadian Press