What was the growth rate of Xylem's advanced digital solutions backlog in 2020 
 resilience for utilities, which is precisely the value proposition of our advanced digital solutions. Pre-pandemic, the business case was already very compelling. But as utility operators worked heroically to keep essential services running, the stresses of the pandemic made it clear that new approaches are required.
Remote monitoring, automated operations and smart infrastructure more broadly continue to see increased demand. Backlog in our advanced digital solutions grew 70% year on year. Although it's from a small base, the trajectory is clear. It puts us in a very attractive position as we grow not only in software platforms, but in all of the digitally enabled parts of our portfolio.
Geographically, India and China will continue to drive high growth. Despite experiencing COVID's earliest impacts, China actually grew last year. And in the three years leading up to 2020, India and China posed a combined average annual growth rates in the double digits. With localization strategies well advanced in both countries, our China and India teams are set to continue delivering impressive growth.
It's also worth mentioning a very solid financial foundation underpinning our growth. With the current cash balance of nearly $1.9 billion, capital deployment is clearly top of mind for us. Even with some debt repayment during the fourth quarter, that number still offers a lot of capacity. Alongside organic investment, M&A remains a top priority, and we intend to be proactive in our deployment of capital, wherever the investment case warrants.
We remain disciplined about valuations, but we do see opportunity for additional investments over the next 18 months. Growth is also important to our creation of social value. We are in the very privileged position that sustainability is baked into our business model and strategy. Our portfolio of solutions has a net positive impact, not only on water, but on a wide range of sustainability outcomes.
We took several bold steps on sustainability in 2020, most notably, our green bond offering. And performance across these metrics continues to put us in a unique leadership position, both in the water sector and more broadly. The team's progress has strengthened our position on a number of sustainability indices. We were recently added to Bloomberg Barclays MSCI Green Bond Index.
Despite that gratifying recognition, we have so much more work to do to achieve our 2025 sustainability goals and to deliver on our mission. I'm now going to turn it over to Sandy to provide end market and segment outlook.
Sandy Rowland -- Chief Financial Officer
Thanks, Patrick. Through 2020, utilities have been reassuringly resilient, down only mid-single digits. As you see in the fourth-quarter results, M&CS and Water Infrastructure revenues held up better than anticipated. Still, our outlook for 2021 reflects a tempered view that utilities have not seen the end of the pandemic impacts quite yet.
We anticipate our utility business overall, which is just north of 50% of Xylem revenues, will grow in the low to mid-single digits in 2021. We expect that same growth rate on the wastewater side as utilities continue to focus on mission-critical applications. And we expect modest recovery in opex growth on a global basis through the year. In the U.S., wastewater capex is likely to be down modestly.
However, the decline should reflect postponements rather than reductions in projects. As you would expect, we have kept close to our utility customers to understand how they are thinking about budgets and funding for this year. And while some uncertainty remains, their deepest concerns have largely abated since the low point of the pandemic. On the clean water side, we anticipate mid single-digit growth.
As I mentioned, large project deployments should begin ramping again from the second quarter, accelerating through the end of the year. The large multiyear metrology deals that we won in 2020 set us up for solid growth this year and beyond. In industrial markets, we've seen good sequential improvement. Short-cycle orders and project 
 resilience for utilities, which is precisely the value proposition of our advanced digital solutions. Pre-pandemic, the business case was already very compelling. But as utility operators worked heroically to keep essential services running, the stresses of the pandemic made it clear that new approaches are required.
Remote monitoring, automated operations and smart infrastructure more broadly continue to see increased demand. Backlog in our advanced digital solutions grew 70% year on year. Although it's from a small base, the trajectory is clear. It puts us in a very attractive position as we grow not only in software platforms, but in all of the digitally enabled parts of our portfolio.
Geographically, India and China will continue to drive high growth. Despite experiencing COVID's earliest impacts, China actually grew last year. And in the three years leading up to 2020, India and China posed a combined average annual growth rates in the double digits. With localization strategies well advanced in both countries, our China and India teams are set to continue delivering impressive growth.
It's also worth mentioning a very solid financial foundation underpinning our growth. With the current cash balance of nearly $1.9 billion, capital deployment is clearly top of mind for us. Even with some debt repayment during the fourth quarter, that number still offers a lot of capacity. Alongside organic investment, M&A remains a top priority, and we intend to be proactive in our deployment of capital, wherever the investment case warrants.
We remain disciplined about valuations, but we do see opportunity for additional investments over the next 18 months. Growth is also important to our creation of social value. We are in the very privileged position that sustainability is baked into our business model and strategy. Our portfolio of solutions has a net positive impact, not only on water, but on a wide range of sustainability outcomes.
We took several bold steps on sustainability in 2020, most notably, our green bond offering. And performance across these metrics continues to put us in a unique leadership position, both in the water sector and more broadly. The team's progress has strengthened our position on a number of sustainability indices. We were recently added to Bloomberg Barclays MSCI Green Bond Index.
Despite that gratifying recognition, we have so much more work to do to achieve our 2025 sustainability goals and to deliver on our mission. I'm now going to turn it over to Sandy to provide end market and segment outlook.
Sandy Rowland -- Chief Financial Officer
 Thanks, Patrick. Through 2020, utilities have been reassuringly resilient, down only mid-single digits. As you see in the fourth-quarter results, M&CS and Water Infrastructure revenues held up better than anticipated. Still, our outlook for 2021 reflects a tempered view that utilities have not seen the end of the pandemic impacts quite yet.
We anticipate our utility business overall, which is just north of 50% of Xylem revenues, will grow in the low to mid-single digits in 2021. We expect that same growth rate on the wastewater side as utilities continue to focus on mission-critical applications. And we expect modest recovery in opex growth on a global basis through the year. In the U.S., wastewater capex is likely to be down modestly.
However, the decline should reflect postponements rather than reductions in projects. As you would expect, we have kept close to our utility customers to understand how they are thinking about budgets and funding for this year. And while some uncertainty remains, their deepest concerns have largely abated since the low point of the pandemic. On the clean water side, we anticipate mid single-digit growth.
As I mentioned, large project deployments should begin ramping again from the second quarter, accelerating through the end of the year. The large multiyear metrology deals that we won in 2020 set us up for solid growth this year and beyond. In industrial markets, we've seen good sequential improvement. Short-cycle orders and project 