India's capacity building role in Afghanistan has indeed, to a significant extent, challenged and arguably shrunk Pakistan's traditional strategic space and influence in the country. This can be understood by examining India's approach and its implications for Pakistan's long-held strategic objectives.

India's engagement in Afghanistan has primarily been through a 'soft power' approach, focusing on development, infrastructure, and humanitarian aid. Key projects include the construction of the Afghan Parliament, the Salma Dam (India-Afghanistan Friendship Dam), the Zaranj-Delaram highway (providing Afghanistan an alternative route to Chabahar Port in Iran, bypassing Pakistan), and extensive training programs for Afghan civil servants, police, and military personnel. India has also invested heavily in education, healthcare, and small-scale community development projects across various provinces.

From Pakistan's perspective, Afghanistan has historically been viewed as a crucial component of its 'strategic depth' against India. Pakistan has sought to maintain significant influence in Afghanistan, often through proxies, to ensure a friendly government on its western border and prevent any perceived encirclement by India. India's growing presence and positive image in Afghanistan were seen by Pakistan as a direct threat to this strategic objective.

How India's role shrunk Pakistan's strategic space:

1. Reduced Afghan Dependence on Pakistan: By providing alternative trade routes (like the Chabahar-Zaranj-Delaram corridor) and investing in Afghanistan's economic self-sufficiency, India offered Afghanistan options that reduced its historical dependence on Pakistan for transit trade and economic lifelines. This directly undermined Pakistan's leverage.
2. Countering Pakistan's Narrative: India's focus on non-military, development-oriented assistance fostered significant goodwill among the Afghan populace and government. This positive image contrasted with Pakistan's often-criticized role, particularly its alleged support for militant groups, thereby weakening Pakistan's narrative and influence.
3. Strengthening Afghan State Institutions: India's support for democratic institutions, capacity building for the Afghan National Security Forces (ANSF), and training for civil servants aimed at strengthening the Afghan state. A strong, stable, and independent Afghan state, aligned with India's vision, inherently reduces the space for external actors, including Pakistan, to manipulate internal dynamics.
4. Geopolitical Balancing: India's presence introduced a significant non-Pakistani influence, contributing to a more multi-polar environment in Afghanistan. This diluted Pakistan's traditional dominance and forced it to contend with another major regional player with strong ties to the Afghan government and people.
5. Connectivity and Regional Integration: India's vision for regional connectivity, often bypassing Pakistan, aimed at integrating Afghanistan into a broader South and Central Asian economic framework. This challenged Pakistan's historical role as the primary gateway for Afghanistan.

Nuances and Limitations:

While India's efforts were substantial, Pakistan's geographical proximity, deep-rooted historical and ethnic ties (especially with Pashtun communities), and its continued influence over certain factions (like the Taliban) meant that its strategic space could not be entirely eliminated. The Taliban's return to power in August 2021 significantly altered the geopolitical landscape, complicating India's position and potentially restoring some of Pakistan's leverage, though the Taliban also seeks diverse international relations and is wary of over-reliance on any single state.

In conclusion, India's capacity building initiatives in Afghanistan, characterized by a focus on development, connectivity, and institutional strengthening, undeniably challenged and, for a period, significantly shrunk Pakistan's traditional strategic space by offering alternatives, fostering goodwill, and promoting a vision of an independent and stable Afghanistan. However, the complex and evolving dynamics of Afghan politics, particularly post-2021, continue to shape the extent of this impact.