Important National and International Days

World Environment Day is celebrated annually on June 5th as designated by the United Nations. It was established in 1972 by the UN General Assembly to mark the opening of the Stockholm Conference on Human Environment. The date has remained consistent since its inception.

November 26th is celebrated as Law Day or Constitution Day in India to commemorate the adoption of the Constitution in 1949. This day marks the completion of the Constituent Assembly's work.

The summer solstice occurs around June 21-22 in the Northern Hemisphere, when the North Pole is tilted closest to the Sun. This results in the maximum daylight hours. Conversely, December 25 is near the winter solstice, the shortest day in the Northern Hemisphere.

CDS-II (Combined Defence Services Examination - II) was indeed held in September in 2011. This follows the typical pattern where CDS-II is conducted in the second half of the year. Note there's a typo in option A (Sepember instead of September), but it's the intended correct answer.

Correct answer is (1). 

The Election Commission of India has decided to celebrate the day its formation- 25 th January every year as the 'National Voters Day'. 

World Habitat Day, (4th October)  its theme, Better City, Better Life.

May 11th is observed as National Technology Day in India to commemorate the Pokhran nuclear tests conducted in 1998. Labour Day is May 1st, AIDS Day is December 1st, and Women's Day is March 8th.

June 5 is observed as World Environment Day annually across the globe. It was established by the United Nations to raise awareness about environmental protection. The other options are observed on different dates: World Health Day (April 7), World Thrift Day (October 31), and World Water Day (March 22).

World Habitat Day is observed on the first Monday of October each year. In 2011, the first Monday of October fell on October 3rd, making this the correct date for that year's celebration.

White Cane Safety Day is observed annually on October 15th to promote awareness of white cane usage and the independence of visually impaired people. This is a fixed-date international observance.

The International Day for Natural Disaster Reduction is observed on the second Wednesday of October each year. This follows a recurring pattern rather than a fixed date, making the timing vary slightly year to year.

International Literacy Day was established by UNESCO in 1966 to raise awareness about the importance of literacy as a matter of dignity and human rights. It is observed globally every year on September 8th.

UNESCO declared September 8th as International Literacy Day in 1966 to remind the international community of the importance of literacy for individuals and societies. It is celebrated worldwide to promote literacy as a matter of dignity and human rights.

The International Day for the Elimination of Racial Discrimination is observed annually on March 21st. It commemorates the 1960 Sharpeville massacre in South Africa, where police killed peaceful demonstrators protesting against apartheid laws.