In the Colorado mountains, a spike in air pollution has been linked to a boom in oil and gas drilling. On the plains of north Texas, there's a drilling boom, too, but some air pollution levels have declined. Opponents of drilling point to Colorado and say it's dangerous. Companies point to Texas and say drilling is safe.

The good news, nearly all sides agree, is that the technology exists to control methane gas leaks and other air pollution associated with drilling. The bad news is that the industry is booming so rapidly in the U.S. that some companies and some regulators can't seem to get ahead of the problems, which could ultimately cost billions of dollars to remedy.

U.S. authorities said a medical helicopter has crashed in northern Illinois, killing all three people on board.

The Federal Aviation Administration reported the helicopter crashed Monday night while traveling from Rockford, near the Wisconsin border, to a hospital about 60 miles (100 kilometers) south in Mendota.

Thousands of Spanish medical workers and residents angered by budget cuts and plans to partly privatize the cherished national health service marched through some of Madrid's most famous squares on Sunday.

More than 5,000 people rallied in Puerta del Sol, according to police estimates, after marching from Neptuno and Cibeles squares. Organizers estimated attendance at 25,000 protesters, many dressed in white and blue hospital scrubs. The march, called "a white tide" by organizers, was the third such large-scale protest this year.

Moon Tae-Hwa stares at his computer, dizzy and nauseous from the hours of porn he's viewed online. He feels no shame — he says he's "cleaning up dirty things."

Moon is among the most successful members of the "Nuri Cops" (roughly "net cops"), a squad of nearly 800 volunteers who help government censors by patrolling the Internet for pornography in their spare time.

The Agriculture Department is responding to criticism over new school lunch rules by allowing more grains and meat in kids' meals.

Agriculture Secretary Tom Vilsack told members of Congress in a letter Friday that the department will do away with daily and weekly limits of meats and grains. Several lawmakers wrote the department after the new rules went into effect in September saying kids aren't getting enough to eat.

Comedian Katt Williams has been arrested in northern California on a felony warrant related to a police chase.

The Sacramento Bee reports (http://bit.ly/UNq5QW ) that Williams was arrested Friday night in Dunnigan, about 25 miles north of Sacramento, by Yolo County deputies.

The Oklahoma City Thunder claimed their eighth straight win as Kevin Durant scored 27 points and Kevin Martin added 24 in a 104-93 win over the Indiana Pacers on Sunday.

A meeting of the NBA's highest-scoring offense and the league's tightest defense went the Thunder's way as they eclipsed 100 points for the 12th straight game.

Barcelona forward Lionel Messi and Atletico Madrid striker Radamel Falcao were unstoppable Sunday on a memorable night when both stars again demonstrated why their teams fill the top two spots in the Spanish league.

Messi broke a 40-year record for most goals in a year by scoring his 85th and 86th goals of 2012 to lead Barcelona to a 2-1 win at Real Betis, while Falcao struck five times as Atletico thrashed Deportivo La Coruna 6-0.

Defending champion Juventus celebrated coach Antonio Conte's return with a win, beating Palermo 1-0 in Serie A on Sunday.

Stephan Lichtsteiner scored five minutes into the second half for Juventus, which also hit the goal-frame twice through Mirko Vucinic.

Robin van Persie scored a stoppage-time winner to give Manchester United a 3-2 win at Manchester City on Sunday, ending the champion's unbeaten start to the Premier League season and taking his side six points clear atop the standings.

Wayne Rooney had set United on the way to avenging last season's double derby defeat to City by scoring twice in the first half against the run of play.