Shell is moving closer to the date when it can start drilling for oil in Arctic waters off Alaska. The company may soon get the Department of the Interior's approval and could begin operations by year's end.

The Bureau of Safety and Environmental Enforcement is reviewing the company's application for permits to drill. If it approves the application, Shell will have everything it would need to start drilling in the Arctic, said Nick Pardi, a spokesman for the bureau.

It would be the last hurdle for Shell (NYSE: RDS.A) in its plan for Arctic exploration, which last week received a boost when federal regulators upheld the company's air pollution permits.

An appeals board with the Environmental Protection Agency upheld the permits on Saturday, increasing the likelihood that Shell start drilling as soon as this summer.

The company wants to drill six exploration wells in an area that may hold as much as 26 billion barrels of oil.

Last December, Shell's plan to drill in the Chukchi Sea between Alaska and Russia was conditionally approved by the Bureau of Ocean Energy Management.

Environmental groups launched a failed offensive to halt Shell's plan. The EPA's air pollution permits were challenged by Resisting Environmental Destruction of Indigenous Lands, Alaska Wilderness League, Center for Biological Diversity, Natural Resources Defense Council, Northern Alaska Environmental Center, Oceana, Pacific Environment, Sierra Club, and the Wilderness Society.

But on Friday, the EPA dismissed their petition and moved the project ahead.

Elsewhere, Shell is currently facing a suit filed in the United Kingdom on behalf of thousands of Nigerian villagers over an oil spill in that country, reported MarketWatch.

In December of 2011, Shell leaked 40,000 barrels of oil when an offshore underwater pipe failed while a tanker was beng loaded.

In Tuesday trading in New York, Shell stock traded down 77 cents to $70.42.