In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

Example input: Article: There are a lot of public libraries in Britain. These libraries have more than one hundred and fifteen million books, not including those libraries of public schools. Public libraries not only lend books, music records but also help children, patients in hospitals and others to get special play readings, film shows and so on. The first public libraries were founded in about the year 1850. Today's public libraries usually have a reading-room, a lending room and a reference room. The greatest and most famous library in Britain is that of the British Library in London. It was founded in 1973 and has over 10, 000, 000 books. It has nearly every magazine, newspaper and book published in Britain and other parts across the world.
Answer: 10,000,000 or less.
Example output: How many books are there in the British Library?
Example explanation: In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.
Q: Article: Milan, the second largest city of Italy, has won an undesirable world record. Of the 54 big cities studied by the World Health Organization and the United Nations, Milan is considered to have the worst air pollution. According to these two10-year studies, the level of air pollution in Milan is twice as high as the levels in Paris and Beijing and three times those in Tokyo and London, and four times that in New York. The reason for Milan's bad pollution, to some experts, is that the city lies in a valley that holds back the poisonous gases. Though Milan has taken some measures to lower the level of pollution, the situation is still worrying. People joke to each other, "If you are traveling to Milan, be sure to bring your gas mask." In order to reduce the use of private cars, in 1979, the government in Milan began an interesting experiment: passengers in the city buses did not have to pay for their tickets.
Answer: Milan's air is considered to be worst polluted in Europe.
A:
Which of the following statements is NOT mentioned in the text?