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In recent Mercer's 2015 annual quality-of-living survey, New Delhi ranks at number 154 out of 230 cities due to bad air quality and pollution. The World Health Organization ranked New Delhi as the world's worst polluted city in 2014 among about 1,600 cities the organization tracked around the world.

What is New Delhi's rank in Mercer's 2015 quality of living survey?
Answer: 154
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Residents of Oklahoma City suffered substantial losses on April 19, 1995 when Timothy McVeigh detonated a bomb in front of the Murrah building. The building was destroyed (the remnants of which had to be imploded in a controlled demolition later that year), more than 100 nearby buildings suffered severe damage, and 168 people were killed. The site has been commemorated as the Oklahoma City National Memorial and Museum. Since its opening in 2000, over three million people have visited. Every year on April 19, survivors, families and friends return to the memorial to read the names of each person lost.

What is the name of the newly renovated site where the bombing occured?
Answer: Oklahoma City National Memorial and Museum
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Some people argue that elevators began as simple rope or chain hoists (see Traction elevators below). An elevator is essentially a platform that is either pulled or pushed up by a mechanical means. A modern-day elevator consists of a cab (also called a "cage", "carriage" or "car") mounted on a platform within an enclosed space called a shaft or sometimes a "hoistway". In the past, elevator drive mechanisms were powered by steam and water hydraulic pistons or by hand. In a "traction" elevator, cars are pulled up by means of rolling steel ropes over a deeply grooved pulley, commonly called a sheave in the industry. The weight of the car is balanced by a counterweight. Sometimes two elevators are built so that their cars always move synchronously in opposite directions, and are each other's counterweight.

How do elevators built in pairs work?
Answer:
their cars always move synchronously in opposite directions,