Questions

• International Workers' Day, also known as Labour Day in some countries, is a celebration of labourers and the working classes that is promoted by the international labour movement, socialists, communists or anarchists. 
• It occurs every year on May Day which is May 1st. It is the day to pay tribute to the Labourers. Without them nothing will complete. 
• In India, the first Labour Day, or May Day, was celebrated in 1923 in Chennai.

Expedite means making an action fast or sooner i.e, to accomplish a work as quickly as possible.

Hence, halt means stop and it is opposite of Expedite.

Nickel

United State Library of Congress, Washington D.C.

• Two Indian companies, Tata SteelBSE and Wipro have been named in the list of world’s most ethical companies by American think tank Ethisphere Institute.

• Ethisphere honors those companies who recognize their role in society to influence and drive positive change in the business community and organizations around the world.

• In 2017, 124 honorees were spanning five continents, 19 countries, and 52 industry sectors.

• Wipro is one of the two information technology companies named in the list, the other being Xerox Corporation.

Steel is not a compound or element. Steel is an alloy of iron and carbon and other elements and hence it is a mixture. Because of its high tensile strength and low cost, it is a major component used in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.