International Day of Yoga is celebrated on which date every year as declared by the United Nations?

Introduction / Context:
International Day of Yoga is one of the most important observance days connected with India on the global stage. It was declared by the United Nations and is celebrated in almost every country with mass yoga demonstrations and awareness activities. For competitive exams, this date is a high priority fact because it combines international recognition, Indian cultural heritage, and health awareness in one question.

Given Data / Assumptions:

• The question explicitly mentions International Day of Yoga as declared by the United Nations.
• The task is to identify the correct fixed date in June on which it is celebrated every year.
• Four options within the month of June are provided, which means the question is testing exact recall of the date.
• We assume the candidate is familiar with recent UN observance days and India related initiatives.

Concept / Approach:
The United Nations General Assembly adopted a resolution in 2014 that declared 21 June as International Day of Yoga following a proposal led by India. The date 21 June was chosen because it is the summer solstice in the northern hemisphere, often associated with balance, energy, and the longest day. To answer correctly, one must recall this key link between 21 June and yoga. Thus, the approach is direct factual recall supported by understanding why that particular date was selected.

Step-by-Step Solution:
Step 1: Recognise that the question refers to the United Nations declared International Day of Yoga. Step 2: Recall that this observance was first celebrated globally in 2015 after the 2014 UN resolution. Step 3: Remember that the date chosen for this day is 21 June every year, which coincides with the summer solstice in the northern hemisphere. Step 4: Compare the remembered date with the four options provided in the question. Step 5: Choose option B, 21 June, since it exactly matches the official date of International Day of Yoga.

Verification / Alternative check:
Candidates can verify this information from standard current affairs compilations, official United Nations lists of observance days, and government of India information portals. News coverage every year shows large yoga events on 21 June at iconic locations such as Rajpath or major stadiums, which reinforces this date in public memory. Additionally, many exam oriented GK notes refer to it as a point of pride for India, which further confirms that 21 June is the correct answer.

Why Other Options Are Wrong:
Option A, 15 June, does not correspond to International Day of Yoga in any official calendar and is therefore incorrect.
Option C, 28 June, is close but not the chosen date for this United Nations observance, so selecting it would be an error.
Option D, 1 June, also has no connection with the official yoga day, making it an incorrect choice.

Common Pitfalls:
Students may confuse International Day of Yoga with other June observances such as World Environment Day or World Music Day. Another pitfall is forgetting that this is a globally recognised UN day and assuming that it might follow a different national pattern. Sometimes test takers remember that the day falls in the later part of June but misplace it as 28 June instead of 21 June. Developing a month wise chart of important international days and revising it regularly helps avoid such confusion.

Final Answer:
International Day of Yoga is celebrated every year on 21 June.