3.3.1. Total Net Virtual Water Import

During 1990–2016, Pakistan's total net virtual water import through the studied commodities has been fluctuating widely from the negative end to the positive end (Figure 2). During 1990–1999, the average annual total net virtual water import remained quite low (1553 Mm3/year); after that, it increased continuously to reach a historical peak of 10,075 Mm<sup>3</sup> in 2008. Since then, it saw a sharp decline to reach a historic low of <sup>−</sup>5998 Mm<sup>3</sup> in 2011 and remained negative in most of the later years. Over the years, the evolution of total net virtual water import (with an annual average of mere 1120 Mm3) seems to indicate that Pakistan has gained some quantities of virtual water through its trade in the major agricultural commodities during 1990–2016. However, further bifurcating total net virtual water import into blue net virtual water import and green net virtual water import would reveal further insights into Pakistan's trade of virtual water, which we present in the next sub-section.

**Figure 2.** Evolution of Pakistan's total net import of virtual (1990–2016). Source: Authors' calculations based on data from Reference [39] (trade volumes) and sources mentioned in the Methods section (VWC).Cotton also contributed significantly towards Pakistan's blue net virtual water import over the years. For cotton, blue net virtual water import was mostly negative during 1990–2001, after which it turned positive, that is, Pakistan became a net importer of cotton from a net exporter after 2001 (Figure 3a). The reason was increased demand for high-grade cotton by Pakistan's domestic industry, which was not met by the domestic production of cotton, due to lower production in some years and lower quality in others [52,53].
