Islamization of North West Bharatavarsha

How did areas of Bharatavarsha - present day Pakistan, become majority-exclusively Muslim? This article does not answer how, but may answer when.

The purpose of this Map is to show that the origin of the almost exclusively Muslim population in 1947 (and absolute Muslim population at present) of North West Bharatavarsha was the very First Muslim invaders/sultanate.
The Map shows the Areas and Years of ANNEXATION by the first 2 invaders of the Ghaznavid Sultanate. This reveals that the areas annexed are much the same as the boundary of Pakistan - which was partitioned on religious lines. Areas ANNEXED by the Ghurid Sultanate - between the Beas and the Yamuna and beyond are 100% Hindu. Thus it is possible that the Islamization of areas until the Beas river occurred during the first sultanate 1026-1185 CE (though the Islamization of Mewat likely occurred during this second Sultanate 1185- CE). The Annexation of Pashtunistan (Kamboja-Gandhara) occurred between 870-1010 CE. Areas of Pakistan to the South of the Ghaznavid Sultanate were ruled by Muslim since 700 CE nor were part of the Ghaznavid sultanate between 1000 and 1200 CE.

The extant of the Ghaznavid Lahore province is falsely said to "span till the Yamuna".
- The territory was taken from the Kamboja Shahi kings whose territorial extant was the Beas river and Lahore was the headquarters.
- When the Ghurid defeated the Ghaznavid in 1185 CE at Lahore the extant of the province was the Beas river and Raja Prithviraja Chauhan had a fort at Bathinda across it. Mention is also thereafter made of minor tributaries of the kingdom of Prithviraj Chauhan in the area.
Therefore the Beas river was the extant of the Ghaznavid Lahore province.
The 2nd Muslim - Ghurid Sultanate extended beyond the Beas - all areas of which were Hindu majority in 1947 and are in India at present.
The Multan kingdom was also clearly not ruled by the Ghaznavid empire.

Did en total forcible conversion take place in these very first Muslim provinces?
I am not aware of / nor have looked up the accounts of the fist Sultanate and thus cannot claim that forcible conversion en total occurred. Before making such a claim, research into the historical accounts is necessary - whether they indicate so or not. What is clear is that the Islamization of now North Pakistan took place during the period of the first Sultanate. Below are some elaborations of this conclusion.
It is known that the annex-or of these regions took hundreds of thousands of people as slaves back to Ghazna after invasions - what would such a Muslim kingdom do to its non Muslim subjects, resulting in a Muslim majority population thereafter ? As pointed out the areas of future Muslim empires did not become exclusively Muslim. I it almost certain that the Rajput clans such as the Janjua, Gakhar, and Khakhar, whom were primary components of the Kamboja Shahi Rajya, which had almost single handedly kept the Turkic Muslim at bay for 50 years - were forced to choose between Islam and death.
The areas adjoining Kashmir to the East were ruled by Chamba. And the hills to its south by Kangra - both these regions historically do not have Muslim majority populations. The hills adjoining Kashmira to the East (PoK) are recorded as joining the Kamboja Shahi in decades of fighting and were Kamboja Shahi and Kashmira territory at various times - these areas are 100% Muslim at present (and in 1947) including Poonch and Rajouri where Hindu are only present in the cities. (Refer to Kashmir Muslim - Region page) These areas were obviously part of the Sultanate territory. Areas of the plains between the Beas and the Ravi rivers did have Muslim populations in 1947 - but Sikh(Hindu denomination) were the majority, and are exclusively Sikh(Hindu denomination) at present. Thus it seems likely that a Muslim majority became almost entirely Sikh(Hindu denomination) in premodern times. Areas East of the Beas are Panjabi-Hindu areas which further proves the Beas as the boundary of the Lahore province. (Refer to the Panjab (India) - Region page)  
The Vale of Kashmira remained independent, a indigenous Muslim migrant from the annexed sultanate areas employed in the army took over the kingdom in 1440. The forced conversion en mass is recorded occurring between 1480-1510.

The annexation/chronology of Sindh and Multan are not present in the map. Islam was is these areas for much longer period and the Muslim rulers are recorded as still having a Surya temple at Mulasthan until 1000 CE (the taxation of which was 30 % of the kingdoms revenue). In 1947 Sindh was 25% Hindu (with some Hindu majority districts) and at present are 10% of Sindh.

Refer to the Kamboja Shahi Rajya for details of the battles proceeding annexations.