One way that a market failure or inefficiency resulting from external economies can be overcome is by government prohibition or regulation. By forbidding an activity that gives rise to an external diseconomy, the external diseconomy can be avoided. For example, by prohibiting the use of automobiles, auto emissions can be avoided. Similarly, by forbidding evening woodworking at home by individual A in the left panel of Figure 12-1, the noise externality that such woodworking creates for individual B would be avoided. Such prohibitions, however, also eliminate the benefit that results from the activities that give rise to the externalities. More reasonable, is regulation that allows the activity that leads to the externality up to the point at which the marginal social benefit from the activity is equal to the marginal social cost. For example, the government could allow individual A to make furniture only 3 hours per evening in the left panel of Figure 12-1, so that the marginal private (and social ) benefit of evening furniture making to individual A equals the marginal social cost (i.e., the individual A plus the marginal costs to individual B-see point Es IN THE FIGURE). Since direct regulation, however, often specifies the production technique to be used to order to limit the external diseconomies , it is usually not cost-efficient.