International Day of Yoga, also called International Yoga Diwas, is celebrated every year on which date?

Introduction / Context:
International Day of Yoga, which many competitive exams in India also call International Yoga Diwas, is an important observance day recognised by the United Nations. It celebrates the ancient Indian practice of yoga and its benefits for physical, mental, and spiritual health. Knowing the exact date of this day helps students answer static general knowledge questions that appear regularly in exams such as SSC, banking, state services, and railways.

Given Data / Assumptions:

• The question asks for the fixed date on which International Day of Yoga is celebrated every year.
• It is a United Nations recognised international day linked to India.
• All answer options are dates in May or June, which suggests that the observance falls in one of these months.
• We assume the question refers to the standard globally accepted date, not a one time event.

Concept / Approach:
The correct approach is to recall the United Nations General Assembly resolution that established International Day of Yoga. In 2014 the UN accepted a proposal from India to declare a specific date for this observance. The chosen date was 21 June, which is the summer solstice in the northern hemisphere and is often regarded as the longest day of the year. Many GK books and current affairs notes highlight this connection between yoga, balance, and the solstice. Therefore the key concept is simple factual recall of a well known international observance date rather than calculation or reasoning.

Step-by-Step Solution:
Step 1: Note that the day asked in the question is International Day of Yoga, also called International Yoga Diwas. Step 2: Recall that the United Nations declared this day through a resolution in 2014 after a proposal by India. Step 3: Remember that the date fixed for this observance is 21 June every year. Step 4: Compare this remembered date with the options provided in the question. Step 5: Identify that option B, which is 21 June, exactly matches the correct date for International Day of Yoga.

Verification / Alternative check:
Students can verify this fact from multiple reliable sources such as NCERT based GK books, government press releases, and the official websites that list United Nations observance days. In exam oriented study material, the trio of important June days is often grouped as World Environment Day on 5 June, World Day Against Child Labour on 12 June, and International Day of Yoga on 21 June. Remembering this cluster of dates helps confirm that 21 June is indeed linked with yoga. News reports about yoga events on 21 June every year, often led by the Prime Minister of India, provide further confirmation in memory.

Why Other Options Are Wrong:
Option A, 21 May, does not correspond to any widely known international yoga related observance and is therefore incorrect.
Option C, 25 May, similarly does not match any official United Nations day connected with yoga.
Option D, 25 June, is close in month but not the correct fixed date chosen by the United Nations for International Day of Yoga, so it is also incorrect.

Common Pitfalls:
A common mistake is to confuse 21 June with some other date in June because several environment and health related days fall in this month. Another pitfall is mixing up the word Diwas with random dates in May, because some national days in India fall in that month. Students sometimes assume that since yoga is Indian in origin, the date must be linked with an Indian national day, but in reality it is a United Nations backed global observance tied to the summer solstice. Careful revision of the list of important international days helps avoid such confusion.

Final Answer:
The International Day of Yoga, also called International Yoga Diwas, is celebrated every year on 21 June.