Excessive irrigation without adequate drainage in parts of Punjab has caused:

The correct answer is: a) Waterlogging and soil salinization.

Excessive irrigation without adequate drainage can lead to waterlogging, which is when the soil becomes saturated with water. This can cause a number of problems, including:

• Soil salinization: When water evaporates from the soil, it leaves behind salts. Over time, these salts can build up in the soil, making it difficult for plants to grow.
• Crop failures: Waterlogged soils are often too wet to support plant growth. This can lead to crop failures, which can have a significant impact on the local economy.
• Soil erosion: Waterlogged soils are more susceptible to erosion, which can lead to the loss of topsoil. Topsoil is essential for plant growth, so its loss can have a devastating impact on agriculture.
• Groundwater contamination: When waterlogged soils seep into groundwater, they can contaminate it with salts and other pollutants. This can make groundwater unsafe for drinking or irrigation.

In order to prevent these problems, it is important to ensure that there is adequate drainage in areas that are being irrigated. This can be done by installing drainage systems or by using alternative irrigation methods, such as drip irrigation.