For the first time, the Indian Air Force (IAF) participated in which multinational air exercise, codenamed PB-18 (Pitch Black 2018), held in Australia and hosted by the Royal Australian Air Force (RAAF)?

Introduction / Context:
Modern air forces regularly participate in multinational exercises to improve interoperability, practice complex air operations and build strategic partnerships. One such important exercise is held in Australia and is known by the codename Pitch Black. The question asks which named exercise, identified as PB-18 for the 2018 edition, saw the Indian Air Force (IAF) taking part for the first time.

Given Data / Assumptions:

• The event occurred in 2018 and carried the code PB-18.
• The host country was Australia, specifically the Royal Australian Air Force (RAAF).
• The Indian Air Force participated for the first time in that particular edition.
• The options list different well known military exercises.

Concept / Approach:
Pitch Black is a large-scale biennial air combat exercise hosted by the Royal Australian Air Force. It involves many nations and focuses on air combat, large formation operations and night flying. When the suffix “PB” and the year 2018 are mentioned together, they clearly point to Exercise Pitch Black 2018. Other named exercises such as Yudh Abhyas and Nomadic Elephant are Indo-United States and Indo-Mongolia joint army exercises, respectively, not air force exercises centred in Australia.

Step-by-Step Solution:
Step 1: Note the key hints: code PB-18, year 2018, host Royal Australian Air Force and first time participation by the Indian Air Force.Step 2: Recall that PB stands for Pitch Black, a major air combat exercise hosted by Australia.Step 3: Recognise that the full name is Exercise Pitch Black.Step 4: Compare with the given options: Exercise Pitch Black, Exercise Desert Strike, Exercise Yudh Abhyas and Exercise Nomadic Elephant.Step 5: Select Exercise Pitch Black as the only option that matches all the clues.

Verification / Alternative check:
Defence news reports from 2018 clearly state that the Indian Air Force participated for the first time in Exercise Pitch Black 2018 in Australia, deploying aircraft such as Sukhoi Su-30 MKI fighters. The exercise involved several air forces and aimed at enhancing joint air operations. None of the other listed exercises are Australian-hosted multinational air force drills, which confirms that Exercise Pitch Black is the correct answer.

Why Other Options Are Wrong:

• Exercise Desert Strike: This name does not correspond to the Australian Pitch Black series and is not associated with PB-18.
• Exercise Yudh Abhyas: This is a bilateral army exercise between India and the United States, not a multinational air combat exercise held in Australia.
• Exercise Nomadic Elephant: This is an army exercise between India and Mongolia, again not linked to Australian air operations.

Common Pitfalls:
Candidates may confuse different military exercises because many sound similar and involve India with various partner countries. A good exam strategy is to categorise them: Pitch Black as a multinational air force exercise in Australia, Yudh Abhyas as an India–United States army drill, and Nomadic Elephant as India–Mongolia army cooperation. Keeping a small table of host country, service branch and partner country helps avoid such confusion.

Final Answer:
The Indian Air Force first participated in the Australian multinational air exercise known as Exercise Pitch Black in 2018 (PB-18).