Introduction:
The Harappan civilization, also known as the Indus Valley civilization, thrived around 2600 to 1900 BCE in the northwestern regions of the Indian subcontinent. During this period, the Harappans developed various forms of art, including pottery. The colors used in Harappan pottery provide valuable insights into their artistic practices and cultural preferences.

Explanation:
Among the different colors used in Harappan pottery, red was the most commonly used color. This can be attributed to several factors:

1. Availability:
Red pigments were readily available to the Harappans. They used natural dyes derived from minerals and plants to color their pottery. Red pigments, such as iron oxide, were easily obtainable from local sources.

2. Symbolic Meaning:
The color red may have held symbolic significance in Harappan culture. Red is often associated with vitality, power, and fertility. Its use in pottery may have been linked to religious or ritualistic beliefs, as pottery was used for various purposes, including storage and offering vessels.

3. Technological Factors:
The Harappans had advanced knowledge of pottery making techniques. They used a variety of firing techniques to achieve different colors on their pottery. Reddish hues were often achieved through oxidizing firing processes, where the pottery was exposed to oxygen during firing. This resulted in the development of red colors on the surface of the pottery.

4. Aesthetic Appeal:
The use of red color in Harappan pottery may have been influenced by aesthetic considerations. The vibrant red hues would have made the pottery visually appealing and attractive. The use of color in pottery was an important aspect of Harappan artistic expression.

Conclusion:
In conclusion, red was the commonly used color in Harappan pottery. Its availability, symbolic meaning, technological factors, and aesthetic appeal likely contributed to its popularity. The use of red color in pottery reflects the artistic practices and cultural preferences of the Harappan civilization.